n,k=map(int,input().split())
m=int(input())
X=k
p=[X]*k
for _ in range(m):
  l,r=map(int,input().split())
  l-=1
  r-=1
  p[l]=min(p[l],r)
for i in range(k):
  for j in range(i+1,k):
    if i!=j and p[i]<X and p[j]<X and p[i]>=p[j]:
      p[i]=X
p=[(i,p[i]) for i in range(k) if p[i]<X]
m=len(p)
p+=[(-1,-1)]
M=998244353
q=[[[0]*(k+1),[0]*(k+1)] for i in range(m+1)]
q[-1][0][0]=1
for h in range(m):
  l,r=p[h]
  for i in range(-1,h):
    ll,rr=p[i]
    for j in range(k+1):
      if rr<l:
        if j+(r-l+1)<=k:
          q[h][0][j+(r-l+1)]+=q[i][1][j]
          q[h][0][j+(r-l+1)]%=M
          q[h][1][j+(r-l+1)]+=q[i][0][j]
          q[h][1][j+(r-l+1)]%=M
      else:
        if j+(r-rr)<=k:
          q[h][0][j+(r-rr)]+=q[i][1][j]
          q[h][0][j+(r-rr)]%=M
          q[h][1][j+(r-rr)]+=q[i][0][j]
          q[h][1][j+(r-rr)]%=M
a=pow(k,n,M)
for i in range(m):
  for j in range(k+1):
    a-=pow(k-j,n,M)*q[i][1][j]
    a+=pow(k-j,n,M)*q[i][0][j]
    a%=M
print(a)