"""

"""

s = {}

A = list(input().split())

for i,c in enumerate(A):

    if c not in s:
        s[c] = len(s)
    A[i] = s[c]

ans = "NO"
for bit in range(2**len(s)):

    P = []
    for i in range(len(s)):
        P.append(bit % 2)
        bit //= 2

    L = ~( ( ~(P[A[0]] & P[A[1]]) ) & P[A[2]] )
    R = ~( ( ~(P[A[3]] & P[A[4]]) ) & P[A[5]] )

    X = ~( L & R )

    if X != 0:
        ans = "YES"

print (ans)