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