#include <fstream>

using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
int P,s,i,c;
int main()
{   f>>P;
    s=0;i=5;
    while(s<P){
        c=i;
        while(c%5==0){
            s++;
            c=c/5;
        }
        i=i+5;
    }
    if(P==0)
        g<<1;
    else
        if(s==P)
            g<<i-5;
    return 0;
}