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

from itertools import permutations

P=list(permutations(D))

for L in P:
    flag=1
    for i in range(5):
        a,b,c=L[i:i+3]

        if a!=b and b!=c and a!=c and a<c:
            pass
        else:
            flag=0
            break

    if flag==1:
        print("YES")
        exit()

print("NO")