// editor3
#include<stdio.h>
int main()
{
    int n, i;
    long long factorial = 1;
    printf("Enter an integer: ");
    scanf("%d", &n);
    if (n < 0){
        printf("Invalid Input\n");
    }
    else{
        for (i = 1; i <= n; ++i){
            factorial *=i;
        }
        print("Factorial of %d = %lld\n",n, factorial);
    }
    return 0;
}