#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const int lim = 4e4;

ll target;

bool check(int x, ll target)
{
    int i, nr = 0;
    ll pw = 1;

    for(i=1; i*i < x; ++i)
        if(x % i == 0)
            nr += 2;

    if(x == i*i)
        ++nr;

    for(int j=1; j<=nr; ++j)
    {
        if(pw > target / x) return 0;
        pw *= x;
    }

    return pw == target;
}

int main()
{
//    freopen("input", "r", stdin);

    cin.sync_with_stdio(false); cin.tie(0);

    cin >> target;

    if(target == 1)
    {
        cout << 1 << '\n';
        return 0;
    }

    int i;

    for(i=1; i<=lim; ++i)
        if(check(i, target))
        {
            cout << i << '\n';
            return 0;
        }

    ll c = cbrt(target);
    if(c * c * c == target)
    {
        int nr = 0;
        for(i=2; i<c; ++i)
            if(c%i == 0) ++nr;

        if(nr == 1) {
            cout << c << '\n';
            return 0;
        }
    }

    c = sqrt(target);
    if(c * c == target)
    {
        bool ok =1;
        for(i=2; i*i<=c; ++i)
            if(c % i == 0) ok= 0;

        if(ok)
        {
            cout << c << '\n';
            return 0;
        }
    }

    cout << -1 << '\n';

    return 0;
}