N25

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#define pii pair <int, int>
using namespace std;

void cv(vector <int> v) {
    for (int i: v) {
        cout << i << ' ';
    }
    cout << "\n";
}

int f(int n) {
    vector <pii> div;
    for (int i = 2; i <= sqrt(n); ++i) {
        if (n % i == 0) {
            int cnt = 0;
            while (n % i == 0) {
                n /= i;
                cnt++;
            }
            div.push_back({i,cnt});
        }
    }
    if (div.size() > 1) {
        return -1;
    }
    if (div[0].second % 2 == 1) {
        return -1;
    }
    int div_num = div[0].second;
    for (int i = 2; i <= sqrt(div_num); ++i) {
        if (div_num % i == 0) {
            return -1;
        }
    }
    return div[0].second;
}


bool cmp(pii a, pii b) {
    return a.second > b.second || a.second == b.second &&  a.first > b.first;
}

int main()
{
    vector <bool> prime(10010,1);
    vector <int> pr = {2,3};
    /*for (int i = 2; i < 10010; ++i) {
        for (int j = 2*i; j < 10010; j += i) {
            prime[j] = 0;
        }
    }
    for (int i = 2; i < 10010; ++i) {
        if (prime[i]) {
            pr.push_back(i);
        }
    }*/
    for (int i = 4; i < 10010; ++i) {
        bool ok = 1;
        for (int j = 2; j <= sqrt(i); ++j) {
            if (i % j == 0) {
                ok = 0;
            }
        }
        if (ok) {
            pr.push_back(i);
        }
    }
    //cv(pr);
    for (int n: pr) {
        //n - простое
        int i = 0;
        while (pow(n, pr[i] - 1) < 10 * pow(10,6);
    }
}