#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,i,j=1;
    cin>>n;
    for(i=1;i<=n;i++){
        j=i*j;
    }
    cout<<j;
}
/**************************************************************
	Problem: 1004
	User: panjinyan
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/