#![allow(unused_imports)]
#![allow(non_snake_case)]
use std::collections::HashMap;
use std::collections::HashSet;

#[allow(unused_macros)]
macro_rules! read {
    ([$t:ty] ; $n:expr) =>
        ((0..$n).map(|_| read!([$t])).collect::<Vec<_>>());
    ($($t:ty),+ ; $n:expr) =>
        ((0..$n).map(|_| read!($($t),+)).collect::<Vec<_>>());
    ([$t:ty]) =>
        (rl().split_whitespace().map(|w| w.parse().unwrap()).collect::<Vec<$t>>());
    ($t:ty) =>
        (rl().parse::<$t>().unwrap());
    ($($t:ty),*) => {{
        let buf = rl();
        let mut w = buf.split_whitespace();
        ($(w.next().unwrap().parse::<$t>().unwrap()),*)
    }};
}

#[allow(dead_code)]
fn rl() -> String {
    let mut buf = String::new();
    std::io::stdin().read_line(&mut buf).unwrap();
    buf.trim_end().to_owned()
}

trait IteratorExt: Iterator + Sized {
    fn vec(self) -> Vec<Self::Item> {
        self.collect()
    }
}
impl<T: Iterator> IteratorExt for T {}

fn main() {
    let w = read!(u64);
    let h = read!(u64);
    let n = read!(u64);
    let cards = read!(u64, u64; n);

    let mut suit_map = HashMap::<u64, u64>::new();
    let mut num_set = HashSet::<u64>::new();
    for card in cards {
        if let Some(x) = suit_map.get_mut(&card.0) {
            *x += 1;
        }
        else {
            suit_map.insert(card.0, 1);
        }

        num_set.insert(card.1); 
    }

    let match_by_suit = {
        let mut tmp = 0;
        for val in suit_map.values() {
            tmp += h - val;
        }
        tmp
    };

    let match_by_num = (w - suit_map.len() as u64) * num_set.len() as u64;

    println!("{}", match_by_num + match_by_suit);
}