#include<stdio.h>
int main ()
{
    int n;
    logn logn 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;
}