#include <iostream>

using namespace std;

int main(){

    int n;
    int s = 1;

        do{
            cout << "Input number ";
            cin >> n;
}          while ( n < 0 || n > 1.0e6);

    if (n >=15){
            cout << "Last three numbers: 000" << '\n';
            return 0;
}
    if (n < 15 ){
            do{
                s = s*n;
                s=s%1000;
                n --;
}              while(n > 1);

            s=s%1000

            cout << "Last three numbers:" << s <<'\n';
}

    return 0;
}