I take WR!!! I don't know what s wrong!!!
---------------------------------MY PROGRAM-------------------------
var N,M,Y:longint;
    a:array[1..15]of byte;
    b:array[1..15]of longint;
    d:array[1..1000]of integer;
    h,x,l:integer;
    i,j,s:longint;
begin
  assign(input,'1110.dat');
  reset(input);
  readln(N,M,Y);
  x:=N;
  for i:=1 to 15 do
  begin
    a[i]:=x mod 2;
    x:=x div 2;
    if x = 0 then break;
  end;
  l:=i;
  for i:=0 to M-1 do
  begin
    b[1]:=i;
    for j:=2 to l do
    begin
      b[j]:=(b[j-1]*b[j-1]) mod M;
    end;
    s:=1;
    for j:=1 to l do if a[j]=1 then
    begin
      s:=(s*b[j]) mod M;
    end;
    if s = Y then
    begin
      inc(h);
      d[h]:=i;
    end;
  end;
  for i:=1 to h-1 do write(d[i],' ');
  if h<>0 then writeln(d[h]);
end.

The answer for test
1 2 3
Should be
-1

GL

> The answer for test
> 1 2 3
> Should be
> -1
>
> GL

0 0 0
_______
Answer: 0

No, because X in the interval [0, M − 1]
I think answer is -1

Since, (0 < N < 999, 1 < M < 999, 0 < Y < 999)
the minimum input is:
1 2 1
with the answer
1

Megakrit, This is best test! Thank you!

Edited by author 27.10.2015 21:21