#![allow(non_snake_case)]

use std::cmp;
use std::io::{ self, prelude::* };

macro_rules! pick {
    ($tokens:expr) => {
        $tokens.next().unwrap().parse().expect("parse error")
    }
}

fn main() {
    let mut s = String::new();
    io::stdin().read_to_string(&mut s).expect("i/o error");
    let mut tokens = s.split_whitespace();

    let x: u64 = pick!(tokens);
    let y: u64 = pick!(tokens);
    let x2: u64 = pick!(tokens);
    let y2: u64 = pick!(tokens);

    let ans = if x == y && x2 == y2 && x2 < x {
        x + 1
    }
    else {
        cmp::max(x, y)
    };

    println!("{}", ans);
}