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')