#include <bits/stdc++.h>

using namespace std;
ifstream fin ("fact.in");
ofstream fout("fact.out");
long long p,cnt2,cnt5,n,cln;
int main()
{
    fin>>p;
    n=1;
    while (1)
        {
            cln=n;
            while (cln%2==0)
                {
                    cnt2++;
                    cln/=2;
                }
            cln=n;
            while (cln%5==0)
                {
                    cnt5++;
                    cln/=5;
                }
            if (min(cnt2,cnt5)==p) {fout<<n; return 0; }
            n++;
        }
    //cout<<n-1;
    return 0;
}