h, w, k = map(int, input().split())

t = [[0 for _ in range(w)] for _ in range(h)]

for i in range(k):
    x, y, v = map(int, input().split())
    t[x-1][y-1] = v

ans = []
for i in range(h):
    for j in range(w):
        tmp = 0
        for x in range(h):
            for y in range(w):
                if x + y >= i + j and x - y >= i - j:
                        tmp += t[x][y]
        ans.append(tmp)
        
                        
print(sum(ans)%998244353)