#explanation in file bishop move
x1 = int(input())
y1 = int(input())
x2 = int(input())
y2 = int(input())
if ((x1 - x2 == 2) or (x1 - x2 == -2)) and ((y1 - y2 == 1) or (y1 - y2 == -1)):
    print('YES')
elif ((x1 - x2 == 1) or (x1 - x2 == -1)) and ((y1 - y2 == 2) or (y1 - y2 == -2)):
    print('YES')
else:
    print('NO')
    