#include <iostream>
#include <fstream>
#define NMax 100000000
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
int i,j,p,k;
int main()
{
    f>>p;
    for(i=1;i<=NMax;i++)
    {
        j=i;
        while(j%5==0)
        j/=5,k++;

        if(k==p)
            break;
    }
    g<<i;
    return 0;
}