#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,n)for (int i = 0; i < int(n); ++i)
#define rrep(i,n)for (int i = int(n)-1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template<class T> void chmax(T& a, const T& b) {a = max(a, b);}
template<class T> void chmin(T& a, const T& b) {a = min(a, b);}
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

using mint = modint998244353;

mint op(mint x, mint y) { return x + y; }
mint e() { return mint(); }
constexpr int FACT_SIZE = 1000000;
mint Fact[FACT_SIZE + 1];
mint iFact[FACT_SIZE + 1];
const auto fact_init = [] {
    Fact[0] = mint::raw(1);
    for(int i = 1; i <= FACT_SIZE; ++i) {
        Fact[i] = Fact[i-1] * i;
    }
    iFact[FACT_SIZE] = Fact[FACT_SIZE].inv();
    for(int i = FACT_SIZE; i; --i) {
        iFact[i-1] = iFact[i] * i;
    }
    return false;
}();

mint comb(int n, int k) {
    if (k == 0) return mint::raw(1);
    assert(n >= 0 && k >= 0);
    if (k > n) return mint::raw(0);
    return Fact[n] * iFact[n - k] * iFact[k];
}

mint icomb(int n, int k) {
    return iFact[n] * Fact[n - k] * Fact[k];
}

mint fact(int n) {return Fact[n];}
mint perm(int n, int k) {
    assert(0 <= n);
    return Fact[n] * iFact[n - k];
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, k;
    cin >> n >> k;
    int m;
    cin >> m;
    vector<P> lr(m);
    for(auto& [l, r]: lr) cin >> l >> r, l--;
    sort(all(lr), [&](const P& lhs, const P& rhs) {
        return
            lhs.second < rhs.second ||
            (lhs.second == rhs.second && lhs.first > rhs.first);
    });
    vector<P> st;
    for(auto [l, r]: lr) {
        if (st.empty() || st.back().first < l) st.emplace_back(l, r);
    }
    lr = move(st);
    m = lr.size();
    vector<segtree<mint, op, e>> dp;
    rep(i, k + 1) dp.emplace_back(m + 1);
    dp[0].set(0, 1);
    int l = 0, r = 0;
    rep(i, k) {
        while(l < m && lr[l].second <= i) l++;
        while(r < m && lr[r].first <= i) r++;
        for(int ii = i; ii >= 0; ii--) {
            mint v = dp[ii].prod(l, m + 1);
            dp[ii+1].set(r, dp[ii+1].get(r) + v);
        }
    }
    mint ans;
    for(int i = 0; i <= k; i++) {
        mint v = dp[i].get(m);
        mint s;
        for(int j = 0; j <= i; j++) {
            mint tmp = comb(i, j) * mint::raw(j).pow(n);
            if ((i - j) % 2 == 0) s += tmp;
            else s -= tmp;
        }
        ans += v * s;
    }
    cout << ans.val() << endl;
}