A = list(map(int,input().split()))

s = sorted(set(A))

for i in range(1<<len(s)):

    sA = []
    for a in A:
        ind = s.index(a)
        if i >> ind & 1:
            sA.append(1)
        else:
            sA.append(0)

    
    a01 = (sA[0] & sA[1]) ^ 1

    a34 = (sA[3] & sA[4]) ^ 1

    a012 = (a01 & sA[2]) ^ 1

    a345 = (a34 & sA[5]) ^ 1

    a05 = (a012 & a345) ^ 1

    if a05:
        print("YES")
        exit()
print("NO")