PROGRAM net;
USES CRT;
VAR  w,j,i,n,k,p,l,m:integer; a,b:array[1..3] of integer; a1,b1:array[1..200] of boolean; f:boolean;
u:array[1..200] of integer;
begin
read(n);
readln(k);
w:=1;
for i:=1 to k do
 begin
 read(a[i]);
 readln(b[i]);
 end;
for i:= 1 to k do
 begin
 a1[i]:=true;
 b1[i]:=true;
 p:=b[i]; j:=1; f:=false;
 while f<>true do
 begin
 f:=true;
   while (a[j]<>p) and (a1[j]=true) do
   j:=j+1;
  a1[j]:=true;
  b1[j]:=true;
  p:=b[j];
  j:=1;
  for l:=1 to k do
   begin
   if a1[l]=false then f:=false;
   if b1[l]=false then f:=false;
   end;

  if f=true then begin u[w]:=a[i];w:=w+1;  end;
 end;
 end;
for i:=1 to w+1 do
begin
if u[w]<u[w+1] then m:=u[w];
end;
write(m);
readln;
end.