N = int(input())
A, B, C = map(int, input().split())

if A == C:
    print('No')
    exit()
if B == C:
    print('Yes')
    exit()

if C < B and B < A:
    print('Yes')
if C < A and A < B:
    print('No')
if A < B and B < C:
    print('Yes')
if A < C and C < B:
    print('Yes')
if B < A and A < C:
    print('No')
if B < C and C < A:
    print('Yes')