#include<cstdio>
using namespace std;
int main()
{unsigned p,i,c,b,x;
int d;
FILE* f=fopen("fact.in","r");
FILE* h=fopen("fact.out","w");
fscanf(f,"%d",&p);
if (p==0)
d=1;
else {
c=0;d=0;
i=1;
do
    {d=i*5;
     c=c+1;
     x=0;b=i;
     while(b%5==0)
      {x=x+1;
      b=b/5;
      }
    c=c+x;
    i=i+1;
    }
while(c<p);
if (c>p)
d=-1;}
fprintf(h,"%d%s",d,"\n");
return 0;}