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

from itertools import permutations


def is_ok(X):
    for i in range(1,6):
        T = X[i-1:i+2]
        if len(set(T)) !=3:
            return False
        if (T[1]==min(T) or T[1] == max(T)) and T[0]<T[2]:
            continue
        else:
            return False
    return True

for p in permutations([i for i in range(7)]):
    
    P = [D[p[i]] for i in range(7)]
    
    if is_ok(P):
        print("YES")
        exit()
print("NO")