from itertools import permutations
D = list(map(int,input().split()))

for X in permutations(range(7),7):
    for i in range(5):
        Y = [D[X[i]],D[X[i+1]],D[X[i+2]]]
        if (max(Y) == Y[1] or min(Y) == Y[1]) and Y[0] < Y[2]:
            continue
        else:
            break
    else:
        print("YES")
        exit()
print("NO")