// Template from https://techracho.bpsinc.jp/jhonda/2019_08_05/78537

// input macro for competive-programming from https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
#[allow(unused_macros)]
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

#[allow(unused_macros)]
macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};

    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };

    ($iter:expr, mut $var:ident : $t:tt $($r:tt)*) => {
        let mut $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

#[allow(unused_macros)]
macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };

    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };

    ($next:expr, [ $t:tt ]) => {
        {
            let len = read_value!($next, usize);
            (0..len).map(|_| read_value!($next, $t)).collect::<Vec<_>>()
        }
    };

    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };

    ($iter:expr, bytes) => {
        read_value!($iter, String).into_bytes()
    };

    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

fn main() {
    use std::io::Read;
    let mut s = String::new();
    std::io::stdin().read_to_string(&mut s).unwrap();

    println!("{}", solve(&s));
}

macro_rules! test {
    ($($input:expr => $output:expr),* $(,)*) => {
        #[test]
        fn solve_test() {
            $(
                assert_eq!(solve($input), $output);
            )*
        }
    };
}

test! {
r#"5 4 2
2 1 1
3 3 4"# => r#"9"#,

r#"5 4 3
2 1 1
3 3 4
1 4 2"# => r#"0"#,

r#"10 10 5
1 6 1
4 1 3
6 9 4
9 4 2
3 1 3"# => r#"64"#,
}

// a = 1: x <= xi
// a = 2: x > xi
// a = 3: y <= yi
// a = 4: y > yi

fn solve(src: &str) -> String {
    input! {
        source = src,
        w: usize, h: usize, n: usize,
        xya: [(usize, usize, usize); n],
    }
    let mut q = vec![vec![false; w]; h];

    // // デバッグコード
    // q[1][2] = true;
    // q[2][2] = true;
    // q[3][3] = true;
    // for i in (0..h).rev() {
    //     let s:Vec<String> = q[i].iter().map(|&j| if j { "o" } else { "x" }.to_string()).collect();
    //     println!("{:?}", s.join(""));
    // }
    // println!("---------------");

    for y in 0..h {
        for x in 0..w {
            for i in 0..n {
                if (xya[i].2 == 1 && x < xya[i].0) || (xya[i].2 == 2 && x >= xya[i].0) || (xya[i].2 == 3 && y < xya[i].1) || (xya[i].2 == 4 && y >= xya[i].1) {
                    q[y][x] = true;
                }
            }
        }
    }

    // // デバッグコード
    // for i in (0..h).rev() {
    //     let s:Vec<String> = q[i].iter().map(|&j| if j { "o" } else { "x" }.to_string()).collect();
    //     println!("{:?}", s.join(""));
    // }
    // println!("---------------");

    // // デバッグコード
    // let s:Vec<usize> = q.iter().map(|qx| qx.iter().filter(|&&n| n).count()).collect();
    // println!("{:?}", s);
    // println!("\n---------------");

    q.iter().map(|qx| qx.iter().filter(|&&n| !n).count()).sum::<usize>().to_string()
}

Measured memory_bytes: 4352