/// Msaa el 5ra
#pragma GCC optimize("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("avx,avx2,fma")

#include "bits/stdc++.h"

using namespace std;

#define pb push_back
#define F first
#define S second
#define f(i, a, b)  for(int i = a; i < b; i++)
#define all(a)  a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define popCnt(x) (__builtin_popcountll(x))
#define int ll

using ll = long long;
using ii = pair<int, int>;
using ull = unsigned long long;

const int N = 1e6 + 5, LG = 18, MOD = (119 << 23) + 1;
const long double PI = acos(-1);
const long double EPS = 1e-7;

int cnt(int x) {
    int cnt = 0;
    for (int i = 1; i * i <= x; i++) {
        if (x % i == 0) {
            cnt += 1;
            if (i * i != x)cnt += 1;
        }
    }
    return cnt;
}

void doWork() {

    int n;
    cin >> n;
    if (n == 1) {
        cout << "1\n";
        return;
    }
    for (int i = 60; i >= 2; --i) {
        int lo = 2, hi = 1000000000;
        while (lo < hi) {
            int md = lo + (hi - lo) / 2;
            __int128 cur = 1;
            for (int j = 0; j < i && cur <= n; j++) {
                cur = cur * md;
            }
            if (cur >= n)
                hi = md;
            else
                lo = md + 1;
        }
        __int128 cur = 1;
        for (int j = 0; j < i && cur <= n; j++) {
            cur = cur * lo;
        }
        if (cur == n && cnt(lo) == i) {
            cout << lo << '\n';
            return;
        }
    }
    cout << "-1\n";
}

int32_t main() {
#ifdef ONLINE_JUDGE
    ios_base::sync_with_stdio(0);
    cin.tie(0);
#endif // ONLINE_JUDGE
    int t = 1;
//    cin >> t;
    while (t--) {
        doWork();
    }
}