#include <iostream>
#include <fstream>
#include <math.h>
using namespace std;
ifstream f("fact.in");
ofstream g("fact.out");
long long na,b,c,a,m,P,i;
int main()
{ f>>P;
na=1;
c=6;
if (P==0) g<<1;
else    {//if (P>=1000000){na=4000004;c=999999;}
for (i=25;c<=P;i=i+25) {m=i; c=c+4; while(m%5==0) {c++;m=m/5;} }

}
while (c!=P) {c--;i=i-5; }
g<<i+5;
    return 0;
}