/* -*- coding: utf-8 -*-
 *
 * 2194.cc:  No.2194 兄弟の掛け引き - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int a, b, c;
  scanf("%d%d%d", &a, &b, &c);

  int n0 = -1, n1 = -1;
  if (c <= b && c % a == 0) n0 = c / a;
  if ((c + b) % a == 0) n1 = (c + b) / a;

  if (n0 < 0 && n1 < 0) puts("-1");
  else {
    if (n0 >= 0) printf("%d\n", n0);
    if (n1 >= 0) printf("%d\n", n1);
  }

  return 0;
}