# -*- coding: utf-8 -*-
"""
No.208 王将
https://yukicoder.me/problems/no/208

"""
import sys
from sys import stdin
input = stdin.readline


def main(args):
    x, y = map(int, input().split())
    ox, oy = map(int, input().split())

    ans = max(x, y)
    if x == y and ox == oy and x > ox:
        ans = max(x, y) + 1
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])