#include<stdio.h>
#include<time.h>
#include<math.h>

using namespace std;

int main()
{

	long long p, i=0, n=0, k=0;
	int j;
	FILE *ifp, *ofp;
	ifp = fopen("fact.in", "r");
	ofp = fopen("fact.out", "w");
	
	fscanf(ifp, "%Ld", &p);
	
	n = p*5-p;
	while (n%5!=0)
		n++;
		
	for (j=1;j<=14;j++)
		k=k+( n / (long long)pow(5,j) );
		
	while (k<p)
	{
		n+=5;
		for (j=1;j<=14;j++)
			if (n % (long long)pow(5,j)==0)
				k++;
	}
	
	
	if (p==0)
		fprintf(ofp, "%d", 1);
	else
		if (k>p)
			fprintf(ofp, "%d", -1);
		else
			fprintf(ofp, "%Ld", n);

	return 0;
}