#include <bits/stdc++.h>
#define rep(i, j, k) for(int i = j; i <= k; ++ i)
#define per(i, j, k) for(int i = j; i >= k; -- i)
using namespace std;
using ll = long long;
const int N = 20;
const ll INF = 1ll << 62;
ll D(ll x) {
    ll res = 1;
    for(ll i = 2; i * i <= x; i ++) {
        if(x % i == 0) {
            int c = 0;
            while(x % i == 0) x /= i, c++;
            if(res * (c + 1) > 100)
                return -1;
            res *= (c + 1);
        }
    }
    if(x > 1) res *= 2;
    return res;
}
ll Pow(ll x, ll k) {
    return k == 1 ? x : x * Pow(x, k-1);
}
int main() {
    ll n, ans = INF;
    cin >> n;
    if(n == 1) {
        cout << 1 << endl;
        return 0;
    }
    for(int k = 2; k <= 61; k ++) {
        ll x = (ll)(powl(n, 1.0 / k) + 0.5);
        if(Pow(x, k) == n && D(x) == k) {
            ans = min(ans, x);
        }
    }
    if(ans == INF) ans = -1;
    printf("%lld\n", ans);
    return 0;
}