#include<stdio.h>
long long factorial(int n){
    if(n<0){
        return -1;
    }else if(n==0){
        return 1;
    }else{
        return n* factorial(n-1);
    }
}
int main()
{
    int n;
    scanf("%d",&n);
    if(n>10||n< -10){
        printf("Input out of range . constraints: -10<=10\n");
    }else{
        long long result=factorial(n);
        if(result==-1){
            printf("Invalid Input\n");
        }else{
            printf("%11d\n",result);
        }
    }
    return 0;
}