#include <stdio.h>
#include <stdlib.h>
FILE *in,*out;int n,P,X,nr,i;
int main()
{
   in=fopen("fact.in","r");
   out=fopen("fact.out","w");
   fscanf(in,"%ld",&P);
for(i=5;nr<P;i=i+5)
   {
       X=i;
       while(X%5==0)
             {X=X/5;
             nr++;
             }

   }


if(nr>0)
fprintf(out,"%d",i-5);
else
if(!P)
fprintf(out,"1");
else
fprintf(out,"-1");


   fclose(in);fclose(out);
    return 0;
}