def main():
    try:
        import pypyjit
        pypyjit.set_param('max_unroll_recursion=-1')
    except:
        pass
    try:
        import sys
        sys.setrecursionlimit(10**7)
    except:
        pass
    from math import sqrt,sin,cos,tan,ceil,radians,floor,gcd,exp,log,log10,log2,factorial,fsum
    import heapq
    from bisect import bisect_left, bisect_right
    import copy
    from collections import deque,Counter,defaultdict
    from itertools import permutations,combinations
    from decimal import Decimal,ROUND_HALF_UP
    #tmp = Decimal(mid).quantize(Decimal('0'), rounding=ROUND_HALF_UP)
    from functools import lru_cache, reduce
    #@lru_cache(maxsize=None)
    from operator import add,sub,mul,xor,and_,or_
    INF = 10**18
    mod1 = 10**9+7
    mod2 = 998244353
    
    #DecimalならPython
    
    H,W,K = map(int, input().split())
    
    x = [0]*(K)
    y = [0]*K
    v = [0]*K

    for i in range(K):
        x[i],y[i],v[i] = map(int, input().split())
    
    ans = 0
    
    for k in range(K):
        for i in range(1,H+1):
            for j in range(1,W+1):
                if x[k]+y[k] >= i+j and x[k]-y[k] >= i-j:
                    ans += v[k]
                ans %= mod2
    
    print(ans)
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
if __name__ == '__main__':
    main()