{ Delphi }

{* 
 * Problem  : 	DESKTOP
 * Contest  : 	UOI-2006 (Dnepropetrovsk)
 * Type     : 	Solution
 * Date     : 	March 30, 2006
 * Author   : 	Andrey Dereza
 * Language :	Pascal
 * Compiler :	Delphi 6.0
 * Algorithm:	Author Solution
 *}

{$A+,B-,C-,D-,E-,F-,G+,H+,I-,J-,K-,L-,M-,N+,O+,P+,Q-,R-,S-,T-,U-,V+,W-,X+,Y-,Z1}
{$MINSTACKSIZE $00004000}
{$MAXSTACKSIZE $00100000}
{$IMAGEBASE $00400000}
program desktop;
{$APPTYPE CONSOLE}

uses
  SysUtils;

type
    TArr=array[0..999] of integer;
var n,from,too:integer;
    verX:array[0..999] of integer;
    verY:array[0..999] of integer;
    verS:array[0..999] of string[50];
    verText1:array[0..999] of integer;
    verTextPos:array[0..999] of integer;
    f:textfile;

    textCnt:array[0..25] of integer;
    textLink:array[0..25] of TArr;// ,0..999] of integer;

    qu:array[0..999] of integer;
    quLen:array[0..999] of integer;
    qustart,qucnt:integer;
    complete:array [0..999] of boolean;

procedure push(num,len:integer);
var nn:integer;
begin
    nn:=quStart+quCnt;
    qu[nn]:=num;
    quLen[nn]:=len;
    Inc(quCnt);
    complete[num]:=true;
end;

function Work:integer;
var len,sel,i,j:integer;
    k,nn,text1,textpos:integer;
    leftnum,rightnum,topnum,bottomnum:integer;
    ll,leftmin,rightmin,topmin,bottommin:double;
    dx,dy:integer;
    ddx,ddy:double;
begin
for i:=0 to n-1 do complete[i]:=false;
qustart:=0;
qucnt:=1;
qu[0]:=from;
qulen[0]:=0;
complete[from]:=true;

while qucnt>0 do
  begin
  sel:=qu[qustart];
  len:=quLen[qustart];
  Inc(quStart);
  Dec(quCnt);
  if sel=too then
     begin
     Result:=len;
     Exit;
     end;
  //literal
  text1:=verText1[sel];
  textPos:=verTextPos[sel];
  for i:=0 to 25 do
    if (i<>text1) and (textCnt[i]>0) and not complete[textLink[i][0]] then
        begin
        push(textlink[i][0],len+1);
        end;
  if (textCnt[text1]>1) then
      begin
      k:=TextPos+1;
      if k>=TextCnt[text1] then k:=0;
      if not complete[textlink[text1][k]] then
         begin
         push(textlink[text1][k],len+1);
         end;
      end;
   //arrow
   leftmin:=1e15;
   rightmin:=1e15;
   topmin:=1e15;
   bottommin:=1e15;
   for i:=0 to n-1 do
    if (i<>sel) then
     begin
       dx:=verX[i]-verX[sel];
       dy:=verY[i]-verY[sel];
       ddx:=dx;
       ddy:=dy;
       ll:=sqr(ddx)+sqr(ddy);
       if (dy>=dx) and (dx>=-dy) then //top
          if (ll<topmin) or
             ((ll=topmin) and ((verX[i]<verX[topnum]) or
                              ((verX[i]=verX[topnum]) and (verY[i]<verY[topnum])))) then
          begin
          topnum:=i;
          topmin:=ll;
          end;
       if (dy<=dx) and (dx<=-dy) then //bottom
          if (ll<bottommin) or
             ((ll=bottommin) and ((verX[i]<verX[bottomnum]) or
                              ((verX[i]=verX[bottomnum]) and (verY[i]<verY[bottomnum])))) then
          begin
          bottomnum:=i;
          bottommin:=ll;
          end;
       if (dy>dx) and (dx<-dy) then //left
          if (ll<leftmin) or
             ((ll=leftmin) and ((verX[i]<verX[leftnum]) or
                              ((verX[i]=verX[leftnum]) and (verY[i]<verY[leftnum])))) then
          begin
          leftnum:=i;
          leftmin:=ll;
          end;
        if (dy<dx) and (dx>-dy) then //right
          if (ll<rightmin) or
             ((ll=rightmin) and ((verX[i]<verX[rightnum]) or
                              ((verX[i]=verX[rightnum]) and (verY[i]<verY[rightnum])))) then
          begin
          rightnum:=i;
          rightmin:=ll;
          end;
     end;
   if (leftmin<1e14) and (not complete[leftnum]) then push(leftnum,len+1);
   if (rightmin<1e14) and (not complete[rightnum]) then push(rightnum,len+1);
   if (topmin<1e14) and (not complete[topnum])then push(topnum,len+1);
   if (bottommin<1e14) and (not complete[bottomnum]) then push(bottomnum,len+1);
  end; {while qucnt>0}
Result:=-1;
end;

  procedure QuickSort(var A: TArr; iLo, iHi: Integer);
  var
    Lo, Hi, T: Integer;
    Mid:string;
  begin
    Lo := iLo;
    Hi := iHi;
    Mid := verS[A[(Lo + Hi) div 2]];
    repeat
      while verS[A[Lo]] < Mid do Inc(Lo);
      while verS[A[Hi]] > Mid do Dec(Hi);
      if Lo <= Hi then
      begin
        T := A[Lo];
        A[Lo] := A[Hi];
        A[Hi] := T;
        Inc(Lo);
        Dec(Hi);
      end;
    until Lo > Hi;
    if Hi > iLo then QuickSort(A, iLo, Hi);
    if Lo < iHi then QuickSort(A, Lo, iHi);
  end;

var res,i,j:integer;
    num:integer;
    ch:char;

    begin
   for i:=0 to 25 do textCnt[i]:=0;

   AssignFile(f,'desktop.dat');
   Reset(f);
   ReadLn(f,n,from,too);
   Dec(from);
   Dec(too);
   for i:=0 to n-1 do
     begin
     Read(f,verX[i],verY[i]);
     ReadLn(f,ch,verS[i]);
     ch:=verS[i][1];
     num:=Ord(ch)-97;
     textLink[num,TextCnt[num]]:=i;
     Inc(textCnt[num]);
     end;
   CloseFile(f);


   for i:=0 to 25 do
    begin
    if TextCnt[i]>1 then
       QuickSort(TextLink[i],0,TextCnt[i]-1);
    for j:=0 to TextCnt[i]-1 do
       begin
       verText1[TextLink[i][j]]:=i;
       verTextPos[TextLink[i][j]]:=j;
       end;
    end;

   res:=Work;
   AssignFile(f,'desktop.sol');
   ReWrite(f);
   WriteLn(f,res);
   CloseFile(f);
end.