#include <cstdio>
#include <cassert>
#include <ctime>

#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <utility>

#define rep(i, n) for (int i = 0; i < int(n); ++i)
#define rep3(i, m, n) for (int i = int(m); i < int(n); ++i)

using namespace std;
using uint64 = unsigned long long;
using uint32 = unsigned;

uint64 divisors[30000];

void solve() {
  uint64 n;
  while (~scanf("%llu", &n)) {
    int sq = sqrt(n);
    int idx = 0;
    rep3(d, 1, sq + 1) if (n % d == 0) {
      divisors[idx++] = d;
      if (uint64(d) * d != n) divisors[idx++] = n / d;
    }
    sort(divisors, divisors + idx);
    rep(i, idx) if (divisors[i] > 2) {
      printf("%llu\n", divisors[i]);
      break;
    }
  }
}

int main() {
  solve();
  return 0;
}