program ping;
var
  n,m,t,i,j,k,e,ans:longint;
  g:array[0..100,0..100] of longint;
begin
  assign(input,'ping.in');
  assign(output,'ping.out');
  reset(input);
  rewrite(output);
  readln(n,m,t);
  for i:=0 to n-1 do
    for j:=0 to n-1 do
      if i<>j then g[i,j]:=1000000000
              else g[i,j]:=0;
  for k:=1 to m do
    begin
      readln(i,j,e);
      g[i,j]:=e;
    end;
  for k:=0 to n-1 do
    for i:=0 to n-1 do
      for j:=0 to n-1 do
        if g[i,j]>g[i,k]+g[k,j]
          then g[i,j]:=g[i,k]+g[k,j];
   writeln(g[0,t]);
   close(input);
   close(output);
end.