MOD = 998244353
H, W, K = map(int, input().split())
xyv = [list(map(int, input().split())) for _ in range(K)]
field = [[0 for _ in range(W)] for _ in range(H)]
for x, y, v in xyv:
    x-=1
    y-=1
    field[x][y] = v
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+=field[x][y]
                    ans%=MOD
print(ans)