#include <fstream>
#include <iostream>
using namespace std;
long long n;
long long pwr(long long n)
{   long long cnt=0;
    for(long long i=5;i<=1000000;i+=5)
    {    long long r=i;
        while(r%5==0) cnt++,r/=5;
        if(cnt>=n) return i;
    }
}
int main()
{   ifstream f("fact.in");
    ofstream g("fact.out");
    f>>n;
    if(n==0) {cout<<1; return 0;}
    g<<pwr(n);
    return 0;
}