import itertools
D=list(map(int,input().split()))
list.sort(D)
def isok(x):
    if x[0]==x[1] or x[1]==x[2] or x[0]==x[2]:
        return False
    if x[0]>x[1] and x[1]<x[2]:
        return True
    if x[0]<x[1] and x[1]>x[2]:
        return True
    return False
ans=False
pat=list(itertools.permutations(D))
for p in pat:
    for i in range(5):
        ans|=isok(p[i:i+3])
if ans:
    print('YES')
else:
    print('NO')