#include <iostream>
#include <fstream>

using namespace std;
int a[5000005];
int main()
{
    ifstream f("fact.in");
    ofstream g("fact.out");
    int p,m=0,k=0,s=0;
    f >> p;
    for(int i=0;i<=5000000;i++)
    {
        a[i+1]=a[i]+5;
    }
    for(int i=1;i<=5000000;++i)
    {
        m=0;
        k=a[i];
        while(a[i]%5==0)
        {
            a[i]=a[i]/5;
            ++m;
        }
        s=s+m;
        if(s==p)
        {
            break;
        }
    }
    g << k;

    return 0;
}