#include<iostream>
#include<fstream>
#include<algorithm>

using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
int i,j,f[4000011],n,p,x;

int main()
{
    fin>>p;
    x=4000010;
    for(i=5;i<=x;i*=5)
        for(j=i;j<=x;j+=i)
            f[j]++;
    if(p==0)
    {
        fout<<1;
        return 0;
    }
    for(i=5;i<=x;i+=5)
    {
        f[i]+=f[i-5];
        if(f[i]==p)
            fout<<i;
    }
    fin.close();
    fout.close();
    return 0;
}