# import sys; input = sys.stdin.buffer.readline
# sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

#処理内容
def main():
	x, y = getlist()
	x2, y2 = getlist()
	if x == y and x2 == y2 and 0 < x2 and x2 < x:
		print(x + 1)
	else:
		print(max(x, y))




if __name__ == '__main__':
	main()