d = map(int,raw_input().split())
a = [d.count(i) for i in sorted(set(d))]
ans = "YES"
if a[0] > 1 or a[-1] > 1 or max(a) > 2:
	ans = "NO"
if len(a) == 5 and a[1] == a[3]:
	ans = "NO"
print ans