import sys
input = sys.stdin.readline

mod=998244353

H,W,K=map(int,input().split())

ANS=0

for tests in range(K):
    x,y,w=map(int,input().split())
    score=0

    for i in range(1,H+1):
        for j in range(1,W+1):
            if x+y>=i+j and x-y>=i-j:
                score+=1

    ANS=(ANS+score*w)%mod

print(ANS)