//2. Suma a n numere  dintr-un sir
#include <fstream>
using namespace std;
  int z,x,k,i;
  ifstream f("fact.in");
  ofstream g("fact.out");
int main()
{
    f>>z;
    if (z==0) {g<<1;
               return 0;}
    for (i=5;i<=100000000;i+=5)
    {
        x=i/5;
        k++;
        while (x%5==0)
        {
            x/=5;
            k++;
        }
        if (k>=z) break;
    }
    g<<i;
    return 0;

}
/*#include <fstream>
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
int s,i,n,m,mij,z,fact5,st,dr;
int main()
{
    f>>n;st=1;dr=500000000;
    while(st<=dr){
    mij=(st+dr)/2;
    m=mij;
    z=0;fact5=5;
    while(m>=fact5){z+=m/fact5;fact5*=5;}
    if(z==n)break;
      else if(z>n)dr=mij-1;
         else st=mij+1;
    }
    mij=mij-mij%5;
    if(n==0)g<<1<<'\n';
    else
    if(st<=dr)  g<<mij<<'\n';
    else g<<-1<<'\n';
    g.close();
    return 0;
}*/