#include <stdio.h>
#include <stdlib.h>
FILE *in,*out; long n,P,X,nr;
int main()
{ int i;
   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%25==0)
       nr=nr+2;
       while(X%5==0)
             {X=X/5;
             nr++;
             }

   }

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


}
else
fprintf(out,"%d",1);



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