#include <bits/stdc++.h>

#define f first
#define s second
#define sz(s) (int)s.size()
#define int long long

using namespace std;

const int N = (int)5e5 + 100;
const int M = N + 7;
const int MOD = 998244353;
const int INF = (int)1e18 + 100;

int d(int n){
    int cnt = 0;
    for(int i = 1; i * i <= n; i++){
        if(n % i == 0){
            cnt++;
            if(i != n / i)
                cnt++;
        }
    }    
    return cnt;
}
int binpow(int a, int b){
    int res = 1;
    while(b--){
        if(res > INF / a)
            return -1;
        res *= a;
    }
    return res;
}

main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
    int x;
    cin >> x;
    if(x == 1){
        cout << "1\n";
        return 0;
    }
    for(int i = 2; i <= 60; i++){
        int l = 1, r = INF, res = -1;
        while(l <= r){
            int mid =  (l + r) >> 1;
            int z = binpow(mid, i);
            if(z != -1 && z <= x)
                res = mid, l = mid + 1;
            else
                r = mid - 1;
        }
        if(res == -1)
            continue;
        int deg = d(res);
        if(binpow(res, deg) == x){
            cout << res << "\n";
            return 0;
        }
    }
    
    cout << "-1\n";
}