// Original-Algorithmus
int ggt(int a, int b) {
  if (a == 0) return b;
  while (b != 0) {
    if (a > b)
      a = a - b;
    else
      b = b - a;
  }
  return a;
}

// modifizierter Algorithmus
int ggt2(int a, int b) {
  int h;
  while (b != 0) {
    h = a % b;
    a = b;
    b = h;
  }
  return a;
}