def u(v):
    a, b, c, d, e, f = v
    return not(not(not(a and b) and c) and not(not(d and e) and f))

l = list(map(int, input().split()))
for i in range(1 << 6):
    v = [0] * 6
    for j in range(6):
        if i >> j & 1:
            v[j] = 1
    f = 1
    for j in range(6):
        for k in range(6):
            if j == k:
                continue
            if l[j] == l[k] and v[j] != v[k]:
                f = 0
    if f:
        if u(v):
            print("YES")
            exit()
print("NO")