use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let v: Vec<i64> = s.split_whitespace().flat_map(str::parse).collect();
	let mut a = 0;
	for n in v[3..].chunks(3) {
		a += n[2]
			* (1..=v[1])
				.map(|w| 0.max(n[0] - (n[1] - w).abs()))
				.sum::<i64>();
		a %= 998244353;
	}
	println!("{a}")
}