#include #include #include #include using namespace std; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n; cin >> n; constexpr int max_n = 3000; vector> neighbor(n); vector matrix(n); for (int i = 0; i < n; ++i) { cin >> matrix[i]; for (int j = 0; j < n; ++j) if (matrix[i][j] == '1') neighbor[i].set(j); } long long sum = 0; for (int i = 0; i < n; ++i) { for (int j = i + 1; j < n; ++j) if (matrix[i][j] == '1') { sum += static_cast((neighbor[i] & neighbor[j]).count()); } } cout << sum / 3 << '\n'; }