#include <stdio.h>

int getN(int p) {
	if ( p == 0 ) 
		return 1;
	const int NMAX = 100000;
	int i = 0, _i = 0, num = 0;
	for ( i = 1; i < NMAX; ++i ) {
		_i = i;
		while( _i % 5 == 0 ) {
			_i /= 5;
			num ++;
		}
		if ( num == p )
			return i;
		if ( num > p )
			return -1;
	}

}

main() {
	freopen("fact.in", "r", stdin);
	freopen("fact.out", "w", stdout);

	int p, res;

	scanf("%d", &p);

	res = getN(p);

	printf("%d", res);

}