use std::collections::HashMap;

use itertools::Itertools;
use proconio::input;

fn main() {
    input! {
        n: usize,
        ab: [(usize, usize); n],
    }

    let mut values = ab.iter().flat_map(|&(a, b)| [a, b]).collect_vec();
    values.push(1);
    values.sort_unstable();
    values.dedup();
    let k = values.len();

    let compress: HashMap<_, _> = values.iter().enumerate().map(|(i, &x)| (x, i)).collect();

    let mut graph = vec![vec![]; k];
    for i in 0..k - 1 {
        graph[i + 1].push(i);
    }

    for &(a, b) in &ab {
        let a = compress[&a];
        let b = compress[&b];
        graph[a].push(b);
    }

    let mut stack = vec![0];
    let mut seen = vec![false; k];
    seen[0] = true;
    let mut ans = 1;
    while let Some(v) = stack.pop() {
        ans = ans.max(values[v]);
        for &u in &graph[v] {
            if !seen[u] {
                seen[u] = true;
                stack.push(u);
            }
        }
    }

    println!("{ans}");
}