program Zadacha;

{$APPTYPE CONSOLE}

uses
  SysUtils;
 var i,j,n,m,k:integer;
 A,B:array[1..20,1..100000] of char;
 c:char;
 f,fl:boolean;
 f1,f2:text;
begin
  { TODO -oUser -cConsole Main : Insert code here }
 assign(f1,'repair.in');
 assign(f2,'repair.out');
 reset(f1);
 rewrite(f2);
 readln(f1,n,m);
 for i:=1 to n do
 begin
  for j:=1 to m do
  begin
   read(f1,A[i,j]);
  end;
  readln(f1);
 end;
 for i:=1 to n do
 begin
  for j:=1 to m do
  begin
   read(f1,B[i,j]);
  end;
  readln(f1);
 end;
 f:=true;
 k:=0;
 while f=true do
 begin
  i:=1;
  f:=false;
  fl:=true;
  while fl=true do
  begin
   j:=1;
   while fl=true do
   begin
    if A[i,j]<>B[i,j] then begin f:=true;; fl:=false; end;
    inc(j);
    if j>m then begin fl:=false; j:=m*2; end;
   end;
   if j=m*2 then fl:=true;
   inc(i);
   if i>n then fl:=false;
  end;
  if f=true then
  begin
   inc(k);
   for i:=1 to n do
   begin
    c:=B[i,m];
    for j:=m downto 2 do
    B[i,j]:=B[i,j-1];
    B[i,1]:=c;
   end;
  end;
 end;
 writeln(f2,k);
 close(f1);
 close(f2);
end.