#include <iostream>
#include <fstream>
using namespace std;
ifstream f;
ofstream g;


long int factorial(long int n){
if (n==0) return 1;
else return n*factorial(n-1);
}

void calculare(){
long int p,n;
f>>p;



            if(p==0) {g<<1;}
            int i=1;
            while(i<100){
                    int s=0;
                int n=factorial(i);
                 cout<<"i = "<<i<<endl;
                while(s!=p&&n%10==0){
                        //if(n%10==0){
                             s++;
                            n=n/10;
                            cout<<"s = "<<s<<endl;}
                     if(s==p) {g<<i;break;}
i++;
}
}


main()
{

    f.open("fact.in");
    g.open("fact.out");

calculare();
cout<<factorial(9);
    f.close();
    g.close();


}