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

mod=998244353
les=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:
                    les+=v[x][y]%mod

print(les%mod)