h,w,k = map(int,input().split())
g = [[0]*w for i in range(h)]
for i in range(k):
    x,y,v = map(int,input().split())
    g[x-1][y-1] = v


mod = 998244353

ans = 0
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 += g[x][y]
                    ans %= mod
print(ans)