~似曾相识燕归来：A了 #include <bits/stdc++.h> using namespace std; int main() { long long n; cin >> n; long long sum = 1; for (long long i = 1; i <= n; ++i) { if (sum > sum % 1000003) { sum = sum % 1000003; } sum *= i; } cout << (sum % 1000003) << endl; }