university/S1/GdCP/a02.c

int sequence(int x, int n){
  if (n < 0) return 0;
  for (int i = 0; i < n; i++) {
    if (x % 2 == 0) x = x/2;
    else x = 3 * x + 1;
    if (x < 0) return -1;
  }
  return x;
};