#include<stdio.h>
int main()
{long long unsigned i,x,n;
long k,p;
FILE *f=fopen("fact.in","r");
FILE *g=fopen("fact.out","w");
fscanf (f,"%ld",&p);
if (p==1) fprintf(g,"1");
else {
i=5;
k=1;
	 while (k<p)
			{i=i+5;
			x=i;
			while (x%5==0) {k++;x=x/5;}
			if (k==p) n=i;
			else n=-1;
			}
fprintf(g,"%llu",n); }
fclose(f);
fclose(g);
return 0;}