use proconio::input;
use proconio::fastout;
use std::cmp::max;

#[fastout]
#[allow(non_snake_case)]
fn main() {
    input! {
        x: isize,
        y: isize,
        x2: isize,
        y2: isize,
    }
    let mut ans = max(x, y);
    if x == y && x2 == y2 && 0 < x2 && x2 < x {
        ans += 1;
    }
    println!("{}", ans);
}