#include using namespace std; int main() { int N; long long M; double PI = acos(-1); cin >> N >> M; vector A(N); vector Px(N); vector Py(N); for (int i = 0; i < N; i++) { cin >> A[i]; Px[i] = cos(2 * PI * A[i] / M); Py[i] = sin(2 * PI * A[i] / M); } long long ans = 0; for (int i = 0; i < N; i++) { for (int j = i + 1; j < N; j++) { for (int k = j + 1; k < N; k++) { long long a = round((Px[i] - Px[j]) * (Px[i] - Px[j]) + (Py[i] - Py[j]) * (Py[i] - Py[j])); long long b = round((Px[j] - Px[k]) * (Px[j] - Px[k]) + (Py[j] - Py[k]) * (Py[j] - Py[k])); long long c = round((Px[i] - Px[k]) * (Px[i] - Px[k]) + (Py[i] - Py[k]) * (Py[i] - Py[k])); if (a + b == c || a + c == b || b + c == a) { ans++; } } } } cout << ans << endl; return 0; }