use std::collections::{HashMap, HashSet};

fn main() {
    proconio::input! {
        h: i64,
        w:i64,
        s: (i64, i64),
        g: (i64, i64),
        b: [String; h],
    }
    let s = (s.1 - 1, s.0 - 1);
    let g = (g.1 - 1, g.0 - 1);
    let b = b
        .into_iter()
        .map(|s| {
            s.chars()
                .map(|x| x.to_digit(10).unwrap() as i8)
                .collect::<Vec<_>>()
        })
        .collect::<Vec<_>>();
    let mut movable: HashMap<(i64, i64), Vec<(i64, i64)>> = HashMap::new();
    // 横
    for y in 0..h {
        for x in 0..w - 1 {
            if (b[y as usize][x as usize] - b[y as usize][x as usize + 1]).abs() <= 1 {
                if let Some(v) = movable.get_mut(&(x, y)) {
                    v.push((x + 1, y));
                } else {
                    movable.insert((x, y), vec![(x + 1, y)]);
                }
                if let Some(v) = movable.get_mut(&(x + 1, y)) {
                    v.push((x, y));
                } else {
                    movable.insert((x + 1, y), vec![(x, y)]);
                }
            }
        }
    }
    for y in 0..h {
        for x in 0..w - 2 {
            if b[y as usize][x as usize] == b[y as usize][x as usize + 2]
                && b[y as usize][x as usize] > b[y as usize][x as usize + 1]
            {
                if let Some(v) = movable.get_mut(&(x, y)) {
                    v.push((x + 2, y));
                } else {
                    movable.insert((x, y), vec![(x + 2, y)]);
                }
                if let Some(v) = movable.get_mut(&(x + 2, y)) {
                    v.push((x, y));
                } else {
                    movable.insert((x + 2, y), vec![(x, y)]);
                }
            }
        }
    }
    // 縦
    for y in 0..h - 1 {
        for x in 0..w {
            if (b[y as usize][x as usize] - b[y as usize + 1][x as usize]).abs() <= 1 {
                if let Some(v) = movable.get_mut(&(x, y)) {
                    v.push((x, y + 1));
                } else {
                    movable.insert((x, y), vec![(x, y + 1)]);
                }
                if let Some(v) = movable.get_mut(&(x, y + 1)) {
                    v.push((x, y));
                } else {
                    movable.insert((x, y + 1), vec![(x, y)]);
                }
            }
        }
    }
    for y in 0..h - 2 {
        for x in 0..w {
            if b[y as usize][x as usize] == b[y as usize + 2][x as usize]
                && b[y as usize][x as usize] > b[y as usize + 1][x as usize]
            {
                if let Some(v) = movable.get_mut(&(x, y)) {
                    v.push((x, y + 2));
                } else {
                    movable.insert((x, y), vec![(x, y + 2)]);
                }
                if let Some(v) = movable.get_mut(&(x, y + 2)) {
                    v.push((x, y));
                } else {
                    movable.insert((x, y + 2), vec![(x, y)]);
                }
            }
        }
    }

    let mut from = HashSet::new();
    let mut visited = HashSet::new();
    from.insert(s);
    let goal = loop {
        let mut to = HashSet::new();
        for from in from {
            if let Some(v) = movable.get(&from) {
                for t in v {
                    if !visited.contains(t) {
                        visited.insert(*t);
                        to.insert(*t);
                    }
                }
            }
        }
        // ゴールに到着したらtrue
        if to.contains(&g) {
            break true;
        }
        // 行ける場所がなくなったらfalse
        if to.is_empty() {
            break false;
        }
        from = to;
    };

    if goal {
        println!("YES");
    } else {
        println!("NO");
    }
}