import itertools

A = input().split()
d = dict()
P = [0] * 6
ct = 0
for i, a in enumerate(A):
    if a in d:
        P[i] = d[a]
    else:
        P[i] = ct
        d[a] = ct
        ct += 1


def nand(x, y):
    return not (x and y)


def solve(P, ct):
    for t in itertools.product((0, 1), repeat=ct):
        if nand(nand(nand(t[P[0]], t[P[1]]), t[P[2]]), nand(nand(t[P[3]], t[P[4]]), t[P[5]])):
            return True
    return False


print("YES" if solve(P, ct) else "NO")