#include <bits/stdc++.h>
using namespace std;

constexpr int mod = 998244353;
int dp[2][1501][1501];

long long modpow(long long a,long long b) {
    long long ans = 1;
    while(b) {
        if(b & 1) {
            (ans *= a) %= mod;
        }
        (a *= a) %= mod;
        b /= 2;
    }
    return ans;
}

long long fac[200005], finv[200005], inv[200005];

void COMinit() {
    fac[0] = fac[1] = finv[0] = finv[1] = inv[1] = 1;
    for (int i = 2; i < 200005; i++) {
        fac[i] = fac[i - 1] * i % mod;
        inv[i] = mod - inv[mod % i] * (mod / i) % mod;
        finv[i] = finv[i - 1] * inv[i] % mod;
    }
}

long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod;
}

int main() {
    int N,K,M;
    cin >> N >> K >> M;
    vector<int>C(K+1,K+1);
    for(int i = 0; i < M; i++) {
        int L,R;
        cin >> L >> R;
        C[L] = min(C[L],R);
    }
    vector<vector<int>>F(K+1,vector<int>(K+1,K+1));
    for(int i = 0; i <= K; i++) {
        int mi = K+1;
        for(int j = i; j <= K; j++) {
            mi = min(mi,C[j]);
            F[i][j] = mi;
        }
    }
    dp[0][0][0] = 1;
    for(int i = 1; i <= K; i++) {
        for(int j = 0; j < i; j++) {
            for(int k = 0; k < i; k++) {
                if(F[j+1][i] > i) {
                    dp[1][j][k] += dp[0][j][k];
                    if(dp[1][j][k] >= mod) dp[1][j][k] -= mod;
                }
                dp[1][i][k+1] += dp[0][j][k];
                if(dp[1][i][k+1] >= mod) dp[1][i][k+1] -= mod;
            }
        }
        for(int j = 0; j <= i; j++) {
            for(int k = 0; k <= i; k++) {
                dp[0][j][k] = dp[1][j][k];
                dp[1][j][k] = 0;
            }
        }
    }
    vector<long long>Pow(K+1);
    for(int i = 0; i <= K; i++) {
        Pow[i] = modpow(i,N);
    }
    COMinit();
    vector<long long>tmp(K+1);
    for(int i = 0; i <= K; i++) {
        for(int j = 0; j <= i; j++) {
            if((i-j)%2 == 0) {
                tmp[i] += Pow[j]*COM(i,j)%mod;
            }
            else {
                tmp[i] += mod-Pow[j]*COM(i,j)%mod;
            }
        }
        tmp[i] %= mod;
    }
    long long ans = 0;
    for(int i = 0; i <= K; i++) {
        for(int j = 0; j <= K; j++) {
            ans += dp[0][i][j]*tmp[j]%mod;
        }
    }
    ans %= mod;
    cout << ans << endl;
}