func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 300005;   const int mod = 1e9 + 7;   const double eps = 1e-8;   const double PI = acos(-1.0);   long long qpow(long long a, long long b, long long p) {     long long res = 1;     while (b) {       if (b & 1) res = res * a % p;       a = a * a % p;       b >>= 1;     }     return res;   }   long long a[N];   int main() {     std::ios::sync_with_stdio(false);     int n, p, k;     while (cin >> n >> p >> k) {       for (int i = 1; i <= n; i++) cin >> a[i];       map<long long, long long> mp;       for (int i = 1; i <= n; i++)         mp[(qpow(a[i], 4, p) - k % p * a[i] % p + p) % p]++;       map<long long, long long>::iterator it = mp.begin();       long long ans = 0;       for (it; it != mp.end(); it++) {         ans += (*it).second * ((*it).second - 1) / 2;       }       cout << ans << endl;     }     return 0;   }   