func_code_string: #include <bits/stdc++.h>   using namespace std;   using ll = long long;   void solve() {     int n, p, k;     cin >> n >> p >> k;     auto f = [&](int x) -> int {       return ((ll)x * x % p * x % p * x % p - (ll)k * x % p + p) % p;     };     map<int, int> cnt;     for (int _ = 0; _ < n; _++) {       int x;       cin >> x;       cnt[f(x)]++;     }     ll res = 0;     for (auto& kp : cnt) {       int i = kp.second;       res += (ll)i * (i - 1) / 2;     }     cout << res;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     solve();     cout << endl;   }   