#include<stdio.h
int main()
{
    
    int n;
    long long factorial = 1;
    if(scanf("%d", &n)!= 1)
    return 0;
    if(n < 0){
        printf("Invalid input");
        return 0;
    }
    else{
        for(int i <1; i <= n;i++){
            factorial *=i;
        }
        printf("%11d", factorial);
    }
    return 0;
}