#include <cstdio>
#define ui unsigned int

inline ui nrzero(ui i)
{
	ui t=0;
	while(i) t+=i/5, i/=5;
	return t;
}

int main()
{
	ui cnt, n, i, p, q;
	
	freopen("fact.in","r",stdin);
	freopen("fact.out","w",stdout);
	scanf("%d", &n);
	
	for(i=cnt=1<<30;cnt;cnt>>=1)
		i-=(i-cnt>=1 && nrzero(i-cnt)>=0) ?cnt:0;
		//if(i-cnt>=1 && nrzero(i-cnt)>=n) i-=cnt;
	i=nrzero(i)==n?i:-1;
	printf("%d\n", i);
	return 0;
}