ITMO РЕВЕРС А почему до этого не раб?

#include <iostream>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <string>
#include <stack>
#include <set>
#include <map>
#define pii pair <int, int>
#define pb(x) push_back(x)
using namespace std;
using ll = long long;
using ld = long double;
using db = double;
void cv(vector <int> &v) {
    for (auto x : v) cout << x << ' ';
    cout << "\n";
}

void cvl(vector <ll> &v) {
    for (auto x : v) cout << x << ' ';
    cout << "\n";
}


void cvv(vector <vector <int> > &v) {
    for (auto x : v) cv(x);
    cout << "\n";
}

void cvb(vector <bool> v) {
    for (bool x : v) cout << x << ' ';
    cout << "\n";
}

void cvs(vector <string>  v) {
    for (auto a : v) {
        cout << a << "\n";
    }
}

void cvp(vector <pii> a) {
    for (auto p : a) {
        cout << p.first << ' ' << p.second << "\n";
    }
    cout << "\n";
}


bool ok(int a0, int a1, int a2, int a3, int a4) {
    int A = 4 * (a0 + 15*a1 + pow(15, 2) * a2 + pow(15, 3) * a3 + pow(15, 4) * a4);
    int B = a4 + 15*a3 + pow(15, 2) * a2 + pow(15, 3) * a1 + pow(15, 4) * a0;
    return A == B;
}


int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    vector <int> v;
    for (int i = 0; i < 15;++i) {
        v.pb(i);
    }
    for (int a4: v) {
        if (a4 == 0) {
            continue;
        }
        for (int a3: v) {
            for (int a2: v) {
                for (int a1: v) {
                    for (int a0: v) {
                        if (ok(a0, a1, a2, a3, a4)) {
                            cout << "OK\n";
                            cout << a0 << ' ' << a1 << ' ' << a2 << ' ' << a3 << ' ' << a4 << "\n";
                            exit(0);
                        }
                    }
                }
            }
        }
    }
}