# 制約が大きければ寄与度か
# まずナイーブにやってみる
# H, W <50なので4重ループでも問題ないはず

mod = 998244353
H, W, K = map(int, input().split())
grid = [[0]*W for i in range(H)]
for i in range(K):
    x, y, v = map(int, input().split())
    grid[x-1][y-1] = v

calc = 0
for i in range(H):
    for j in range(W):
        subcalc = 0
        for x in range(H):
            for y in range(W):
                if x+y >= i+j and x-y >= i-j:
                    subcalc += grid[x][y]
                    subcalc %= mod
        calc += subcalc
        calc %= mod
print(calc%mod)