homework/666/02.2.2.cpp

#include<iostream>
using namespace std;
int bjdx(int a){
    int b=1;
    for(int i=1;i<=a;i++)
        b=b*i;

    return b;
    }
int main(){
    int pdd;
    cin>>pdd;
    cout<<bjdx(pdd)<<endl;
    
    return 0;
}