def solve():
    H,W,K=map(int,input().split())

    T=[[0]*(W+1) for _ in range(H+1)]
    for k in range(K):
        x,y,v=map(int,input().split())
        T[x][y]=v

    Ans=0
    for i in range(1,H+1):
        for j in range(1,W+1):
            for x in range(1,H+1):
                for y in range(1,W+1):
                    if x+y>=i+j and x-y>=i-j:
                        Ans+=T[x][y]
    return Ans%998244353

#==================================================
print(solve())