H,W,K=map(int,input().split())
S=[[0 for _ in range(W)] for _ in range(H)]
for i in range(K):
    a,b,c=map(int,input().split())
    S[a-1][b-1]+=c
    
ans=0
mod=998244353
for i in range(H):
    for j in range(W):
        for x in range(H):
            for y in range(W):
                if x+y>=i+j and x-y>=i-j:
                    ans+=S[x][y]
                    ans%=mod
print(ans)