#include <iostream>

using namespace std;

#define int long long

const int MOD = 998244353;

int fac[5000005];
int inv[5000005];

int32_t main() {
	int t, N;
	cin >> t >> N;
	fac[0] = inv[0] = 1;
	fac[1] = inv[1] = 1;
	for (int i = 2; i <= N; i++) {
		fac[i] = 1LL * fac[i - 1] * i % MOD;
		inv[i] = 1LL * (MOD - MOD / i) * inv[MOD % i] % MOD;
	}
	for (int i = 1; i <= N; i++)
		inv[i] = 1LL * inv[i - 1] * inv[i] % MOD;
	int ans = 0;
	while (t--) {
		int n, m;
		cin >> n >> m;
		int x = 1LL * fac[n] * inv[m] % MOD * inv[n - m] % MOD;
		ans ^= x;
	}
	cout << ans << "\n";

	return 0;
}