#include<stdio.h>

int fac(int n) {
if ( n == 0 )
	return 1;
else return n*fac(n-1);
}

int main(){
int s=0,q=0,p;
int res=0;
FILE *in,*out;

in = fopen("fact.in","r");
fscanf(in,"%d",&p);

  if (p !=0 ){
	for (i=5;s<=p;i=i+5){
		q=i;
		while(q%5==0){
			s+=1;
			q/=5;
		}
	}
  if(s!=p) 
	res = -1;
  else res=i;
  }
	else res=1;		



fclose(in);
out = fopen("fact.out","w");
fprintf(out,"%d",res);
fclose(out);
return 0;
}