/* -*- coding: utf-8 -*-
 *
 * 1312.cc:  No.1312 Snake Eyes - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const long long LINF = 1LL << 62;

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

/* main */

int main() {
  ll n;
  scanf("%lld", &n);

  // k >= 3
  ll s;
  for (int p = 2; (s = 1 + p + (ll)p * p) <= n; p++) {
    while (s <= n) {
      if (n % s == 0 && n / s < p) {
	printf("%d\n", p);
	return 0;
      }
      s = s * p + 1;
    }
  }

  // k == 2 or k == 1
  ll minp = LINF;
  
  for (int d = 1; (ll)d * d <= n; d++)
    if (n % d == 0) {
      ll m = n / d;

      ll p2 = m - 1;
      if (p2 > d && minp > p2) minp = p2;

      ll p1 = m;
      if (p1 > d && minp > p1) minp = p1;
    }

  printf("%lld\n", minp);
  return 0;
}