from itertools import permutations, product

def solution(A):
    # Step 1: Convert into domino pairs
    dominoes = [(A[i], A[i+1]) for i in range(0, len(A), 2)]

    # Step 2: Try all permutations
    for perm in permutations(dominoes):

        # Step 3: Try all rotations (0 = original, 1 = flipped)
        for flips in product([0, 1], repeat=6):

            # Apply flips
            d = []
            for i in range(6):
                if flips[i] == 0:
                    d.append(perm[i])
                else:
                    d.append((perm[i][1], perm[i][0]))

            # Pyramid layout:
            # Bottom: d[0], d[1], d[2]
            # Middle: d[3], d[4]
            # Top: d[5]

            # Check conditions:
            if (
                # Middle over bottom
                d[3][0] == d[0][1] and d[3][1] == d[1][0] and
                d[4][0] == d[1][1] and d[4][1] == d[2][0] and

                # Top over middle
                d[5][0] == d[3][1] and d[5][1] == d[4][0]
            ):
                return "YES"

    return "NO"