#ifndef hari64 #include // #pragma GCC target("avx2") // #pragma GCC optimize("O3") // #pragma GCC optimize("unroll-loops") #define debug(...) #else #include "util/viewer.hpp" #define debug(...) viewer::_debug(__LINE__, #__VA_ARGS__, __VA_ARGS__) #endif using namespace std; constexpr int INF = 1001001001; constexpr long long INFll = 1001001001001001001; template bool chmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; } template bool chmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; } int main() { cin.tie(0); ios::sync_with_stdio(false); long long N, P; cin >> N >> P; vector As(N); for (int i = 0; i < N; i++) { cin >> As[i]; } long long ans = 0; long long Pe = 1; while (Pe < INFll / P) { Pe *= P; map m; for (int i = 0; i < N; i++) { m[As[i] % Pe]++; } for (const auto& [key, value] : m) { ans += 1ll * value * (value - 1) / 2; } } cout << ans << endl; return 0; }