#the modulus operator is % in Python
5 % 3
#returns remainder: 2
x1 = int(input())
y1 = int(input())
x2 = int(input())
y2 = int(input())
if( ( (x2-x1) % 2 = 1 and (y2-y1) % 2 = 1 ) or ( (x2-x1) % 2 = 0 and (y2-y1) % 2 = 0) ):
print('YES')
else:
print('NO')