mod=998244353

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

D=dict()

for _ in range(k):
    x,y,v=map(int,input().split())
    D[(x-1,y-1)]=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 and (x,y) in D:
                    ans+=D[(x,y)]
                    ans%=mod

print(ans)