N, K = map(int,input().split())
M = int(input())
R = [-1]*(K+1)
for i in range(M):
    l,r = map(int,input().split())
    R[r] = max(R[r], l)

for i in range(K+1):
    if R[i] == -1:
        continue
    for j in range(i+1,K+1):
        if R[j] <= R[i]:
            R[j] = -1

MOD = 998244353
dp1 = [[[0 for k in range(2)] for j in range(K+1)] for i in range(K+1)]
dp2 = [[[0 for k in range(2)] for j in range(K+1)] for i in range(K+1)]

dp1[0][0][0] = dp2[0][0][0] = 1

for i in range(1,K+1):
    for j in range(K+1):
        v = [0, 0]
        if R[i]!= -1 and j > 0:
            L = R[i]
            for k in range(2):
                v[k]+=dp2[i-1][j-1][k^1]
                if j-(i-L+1)>=0:
                    v[k]-=dp2[L-1][j-(i-L+1)][k^1]
                    v[k]+=dp1[L-1][j-(i-L+1)][k^1]
        
        for k in range(2):
            v[k]%=MOD;
            dp1[i][j][k] = v[k] + dp1[i-1][j][k]
            if dp1[i][j][k]>=MOD:
                dp1[i][j][k]-=MOD
            dp2[i][j][k] = v[k]
            if j-1>=0:
                dp2[i][j][k] += dp2[i-1][j-1][k]
                if dp2[i][j][k]>=MOD:
                    dp2[i][j][k]-=MOD

ans = 0
for i in range(K):
    ans += (dp1[K][i][0]-dp1[K][i][1])*pow(K-i,N,MOD)
    ans %= MOD

print(ans)