#include <fstream>
using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");

int p;
int nr2,nr5,per;

int main()
{
    fin>>p;

    if(p==0)
        fout<<"1";
    else
    {
        int nr=2,cop;
        while(true)
        {
            cop=nr;
            while(nr%10==0)
            {
                nr/=10;
                per++;
            }
            while(nr%2==0)
            {
                nr/=2;
                nr2++;
            }
            while(nr%5==0)
            {
                nr/=5;
                nr5++;
            }

            while(nr2>0 && nr5>0)
            {
                per++;
                nr2--;
                nr5--;
            }

            if(per>=p)
            {
                fout<<cop;
                break;
            }
            else
                nr=cop+1;
        }
    }

    return 0;
}