#![allow(unused_macros, unused_imports, dead_code)]
use std::any::TypeId;
use std::cmp::{max, min, Reverse};
use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, VecDeque};
use std::mem::swap;
use std::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Rem, Sub, SubAssign};

mod my_string {
    use std::ops::{Index, IndexMut};
    use std::slice::SliceIndex;
    #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
    pub struct Str {
        vc: Vec<char>,
    }
    impl Str {
        pub fn new() -> Self {
            Self { vc: vec![] }
        }
        pub fn from(s: &str) -> Self {
            Self {
                vc: s.to_string().chars().collect::<Vec<char>>(),
            }
        }
        pub fn len(&self) -> usize {
            self.vc.len()
        }
        pub fn clear(&mut self) {
            self.vc.clear()
        }
        pub fn is_empty(&self) -> bool {
            self.vc.is_empty()
        }
        pub fn first(&self) -> Option<&char> {
            self.vc.first()
        }
        pub fn last(&self) -> Option<&char> {
            self.vc.last()
        }
        pub fn push(&mut self, c: char) {
            self.vc.push(c);
        }
        pub fn push_str(&mut self, s: &str) {
            for c in s.to_string().chars().collect::<Vec<char>>().into_iter() {
                self.push(c);
            }
        }
        pub fn pop(&mut self) -> Option<char> {
            self.vc.pop()
        }
        pub fn into_iter(self) -> std::vec::IntoIter<char> {
            self.vc.into_iter()
        }
        pub fn iter(&self) -> std::slice::Iter<char> {
            self.vc.iter()
        }
        pub fn iter_mut(&mut self) -> std::slice::IterMut<char> {
            self.vc.iter_mut()
        }
        pub fn swap(&mut self, a: usize, b: usize) {
            self.vc.swap(a, b);
        }
        pub fn reverse(&mut self) {
            self.vc.reverse();
        }
        pub fn find(&self, p: &Str) -> Option<usize> {
            let s: String = self.vc.iter().collect::<String>();
            let p: String = p.vc.iter().collect::<String>();
            s.find(&p)
        }
        pub fn rfind(&self, p: &Str) -> Option<usize> {
            let s: String = self.vc.iter().collect::<String>();
            let p: String = p.vc.iter().collect::<String>();
            s.rfind(&p)
        }
        pub fn into_values(self, base: char) -> Vec<usize> {
            self.vc
                .into_iter()
                .map(|c| (c as u8 - base as u8) as usize)
                .collect::<Vec<usize>>()
        }
        pub fn sort(&mut self) {
            self.vc.sort();
        }
        pub fn remove(&mut self, index: usize) -> char {
            self.vc.remove(index)
        }
    }
    impl std::str::FromStr for Str {
        type Err = ();
        fn from_str(s: &str) -> Result<Self, Self::Err> {
            Ok(Str {
                vc: s.to_string().chars().collect::<Vec<char>>(),
            })
        }
    }
    impl<Idx: SliceIndex<[char]>> Index<Idx> for Str {
        type Output = Idx::Output;
        fn index(&self, i: Idx) -> &Self::Output {
            &self.vc[i]
        }
    }
    impl<Idx: SliceIndex<[char]>> IndexMut<Idx> for Str {
        fn index_mut(&mut self, index: Idx) -> &mut Self::Output {
            &mut self.vc[index]
        }
    }
    impl std::ops::Add<Str> for Str {
        type Output = Str;
        fn add(self, rhs: Self) -> Self::Output {
            let mut ret = self;
            for c in rhs.into_iter() {
                ret.vc.push(c);
            }
            ret
        }
    }
    impl std::ops::AddAssign<Str> for Str {
        fn add_assign(&mut self, rhs: Self) {
            for c in rhs.into_iter() {
                self.vc.push(c);
            }
        }
    }
    impl std::ops::Add<char> for Str {
        type Output = Str;
        fn add(self, rhs: char) -> Self::Output {
            let mut ret = self;
            ret.vc.push(rhs);
            ret
        }
    }
    impl std::ops::AddAssign<char> for Str {
        fn add_assign(&mut self, rhs: char) {
            self.vc.push(rhs);
        }
    }
    impl std::fmt::Display for Str {
        fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
            write!(f, "{}", self.vc.iter().collect::<String>())
        }
    }
    impl std::fmt::Debug for Str {
        fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
            write!(f, "{}", self.vc.iter().collect::<String>())
        }
    }
}
use my_string::Str;

mod procon_reader {
    use std::fmt::Debug;
    use std::io::Read;
    use std::str::FromStr;
    pub fn read<T: FromStr>() -> T
    where
        <T as FromStr>::Err: Debug,
    {
        let stdin = std::io::stdin();
        let mut stdin_lock = stdin.lock();
        let mut u8b: [u8; 1] = [0];
        loop {
            let mut buf: Vec<u8> = Vec::with_capacity(16);
            loop {
                let res = stdin_lock.read(&mut u8b);
                if res.unwrap_or(0) == 0 || u8b[0] <= b' ' {
                    break;
                } else {
                    buf.push(u8b[0]);
                }
            }
            if !buf.is_empty() {
                let ret = String::from_utf8(buf).unwrap();
                return ret.parse().unwrap();
            }
        }
    }
    pub fn read_vec<T: std::str::FromStr>(n: usize) -> Vec<T>
    where
        <T as FromStr>::Err: Debug,
    {
        (0..n).into_iter().map(|_| read::<T>()).collect::<Vec<T>>()
    }
    pub fn read_vec_sub1(n: usize) -> Vec<usize> {
        (0..n)
            .into_iter()
            .map(|_| read::<usize>() - 1)
            .collect::<Vec<usize>>()
    }
    pub fn read_mat<T: std::str::FromStr>(h: usize, w: usize) -> Vec<Vec<T>>
    where
        <T as FromStr>::Err: Debug,
    {
        (0..h)
            .into_iter()
            .map(|_| read_vec::<T>(w))
            .collect::<Vec<Vec<T>>>()
    }
}
use procon_reader::*;


fn exit_by<T: std::fmt::Display>(msg: T) {
    println!("{}", msg);
    std::process::exit(0);
}

mod gcd {
    use std::cmp::{PartialEq, PartialOrd};
    use std::ops::{Add, AddAssign, Div, Mul, MulAssign, Neg, Rem, RemAssign, Sub, SubAssign};
    pub fn gcd<T: Copy + Sub<Output = T> + Rem<Output = T> + PartialEq>(a: T, b: T) -> T {
        #[allow(clippy::eq_op)]
        let zero = a - a;
        if b == zero {
            a
        } else {
            gcd(b, a % b)
        }
    }
    // returns (p, q) s. t. ap + bq = gcd(a, b)
    pub fn ext_gcd<
        T: Eq
            + Copy
            + Sub<Output = T>
            + SubAssign
            + Mul<Output = T>
            + Div<Output = T>
            + Rem<Output = T>,
    >(
        a: T,
        b: T,
    ) -> (T, T) {
        #[allow(clippy::eq_op)]
        let zero = b - b;
        #[allow(clippy::eq_op)]
        let one = b / b;
        if a == zero {
            return (zero, one);
        }
        // (b % a) * x + a * y = gcd(a, b)
        // b % a = b - (b / a) * a
        // ->
        // (b - (b / a) * a) * x + a * y = gcd(a, b)
        // a * (y - (b / a) * x) + b * x = gcd(a, b)
        let (x, y) = ext_gcd(b % a, a);
        (y - b / a * x, x)
    }
    // Chinese Remainder Theorem
    // when exists, returns (lcm(m1, m2), x) s.t. x = r1 (mod  m1) and x = r2 (mod m2)
    fn chinese_rem_elem2<
        T: Eq
            + Copy
            + Neg<Output = T>
            + PartialOrd
            + Add<Output = T>
            + AddAssign
            + Sub<Output = T>
            + SubAssign
            + Mul<Output = T>
            + Div<Output = T>
            + Rem<Output = T>
            + RemAssign,
    >(
        m1: T,
        r1: T,
        m2: T,
        r2: T,
    ) -> Option<(T, T)> {
        #[allow(clippy::eq_op)]
        let zero = m1 - m1;
        #[allow(clippy::eq_op)]
        let one = m1 / m1;
        let (p, _q) = ext_gcd(m1, m2);
        let g = gcd(m1, m2);
        if (r2 - r1) % g != zero {
            None
        } else {
            let lcm = m1 * (m2 / g);
            let mut r = r1 + m1 * ((r2 - r1) / g) * p;
            if r < zero {
                let dv = (-r + lcm - one) / lcm;
                r += dv * lcm;
            }
            r %= lcm;
            Some((lcm, r))
        }
    }
    // Chinese Remainder Theorem
    // when exists, returns (lcm(mods), x) s.t. x = r_i (mod  m_i) for all i.
    pub fn chinese_rem<
        T: Eq
            + Copy
            + Neg<Output = T>
            + PartialOrd
            + Add<Output = T>
            + AddAssign
            + Sub<Output = T>
            + SubAssign
            + Mul<Output = T>
            + Div<Output = T>
            + Rem<Output = T>
            + RemAssign,
    >(
        mods: &[T],
        rems: &[T],
    ) -> Option<(T, T)> {
        debug_assert!(mods.len() == rems.len());
        #[allow(clippy::eq_op)]
        let zero = mods[0] - mods[0];
        #[allow(clippy::eq_op)]
        let one = mods[0] / mods[0];
        let mut lcm = one;
        let mut rem = zero;
        for (m, r) in mods.iter().copied().zip(rems.iter().copied()) {
            if let Some((nlcm, nrem)) = chinese_rem_elem2(lcm, rem, m, r) {
                lcm = nlcm;
                rem = nrem;
            } else {
                return None;
            }
        }
        Some((lcm, rem))
    }
}
use gcd::*;

mod power_with_identity {
    use std::ops::Mul;
    pub fn power_with_identity<T: Copy + Mul<Output = T>>(identity: T, base: T, mut p: usize) -> T {
        #[allow(clippy::eq_op)]
        let mut ret = identity;
        let mut mul = base;
        while p > 0 {
            if p & 1 != 0 {
                ret = ret * mul;
            }
            p >>= 1;
            mul = mul * mul;
        }
        ret
    }
}
use power_with_identity::power_with_identity;

/*************************************************************************************
*************************************************************************************/

fn main() {
    let md = 998244353;
    let h = read::<usize>();
    let w = read::<usize>();
    let k = read::<usize>();
    let mut trs = vec![vec![0; w]; h];
    for _ in 0..k {
        let y = read::<usize>() - 1;
        let x = read::<usize>() - 1;
        let v = read::<i64>();
        trs[y][x] = v % md;;
    }
    let trs = trs;
    let mut ans = 0;
    for y in 0..h {
        for x in 0..w {
            for i in 0..h {
                for j in 0..w {
                    if y + x >= i + j {
                        if y as i64 - x as i64  >= i as i64  - j as i64  {
                            ans += trs[y][x];
                            ans %= md;
                        }
                    }
                }
            }
        }
    }
    println!("{}", ans);
}