ABC055B - Training Camp

問題：B - Training Camp

#include <iostream>
using namespace std;

#define FOR(i, a, b) for (int i = a; i < (b); ++i)

int main(void) {
    const int MOD = 1e9 + 7;
    int n;
    long long ans = 1;

    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> n;
    FOR(i, 1, n + 1) {
        ans *= i;
        ans %= MOD;
    }

    cout << ans << "\n";
    return 0;
}