I have WA on #10.
 Here is a prog:
type
 long = record x,y : longint; rx,cx,ry,cy : real; end;
var
 d : array [1..100] of real;
 a : array [1..100] of long;
 i,j,n,m,s : longint;
procedure inp;
begin
 fillchar(d,sizeof(d),0);
 read(n,m,s,d[s]);
 for i := 1 to m do
 with a[i] do read(x,y,rx,cx,ry,cy);
end;
procedure find;
begin
 for i := 1 to n-1 do
 for j := 1 to m do
 begin
  if ((d[a[j].x]-a[j].cx)*a[j].rx > d[a[j].y])
  then d[a[j].y] := (d[a[j].x]-a[j].cx)*a[j].rx;
  if ((d[a[j].y]-a[j].cy)*a[j].ry > d[a[j].x])
  then d[a[j].x] := (d[a[j].y]-a[j].cy)*a[j].ry;
 end;
end;
procedure out;
begin
 for i := 1 to m do
 begin
  if ((d[a[i].x]-a[i].cx)*a[i].rx > d[a[i].y])
  then begin writeln('YES'); halt; end;
  if ((d[a[i].y]-a[i].cy)*a[i].ry > d[a[i].x])
  then begin writeln('YES'); halt; end;
 end;
 writeln('NO');
end;
begin
 inp;
 find;
 out;
end.