import sys

inputs = sys.stdin.readline

"""再帰関数のときセット
sys.setrecursionlimit(10**7)
import pypyjit
pypyjit.set_param('max_unroll_recursion=-1')
"""

MOD = 998244353


def main():
    H, W, K = map(int, inputs().split())
    Grid = [[0] * W for _ in range(H)]

    for _ in range(K):
        i, j, v = map(int, inputs().split())
        Grid[i - 1][j - 1] = v

    ans = 0
    for i in range(H):
        for j in range(W):
            for ii in range(H):
                for jj in range(W):
                    if ii + jj >= i + j and ii - jj >= i - j:
                        ans += Grid[ii][jj]
                        ans %= MOD
    print(ans)


if __name__ == '__main__':
    main()