#include<bits/stdc++.h>
const int MOD = 998244353;  
using namespace std;  
long long modPower(long long a, long long t) { 
    long long now = a, ret = 1; 
    while (t) { 
        if (t & 1) 
            ret =now*(ret % MOD)%MOD; 
        now=now*(now % MOD)%MOD; 
        t >>= 1; 
    } 
    return ret; 
} 
long countWays(int n, int m, int k) 
{ 
    if (k == -1 && (n + m) % 2 == 1) 
        return 0; 
    if (n == 1 || m == 1) 
        return 1; 
    return (modPower(modPower((long long)2, n - 1), m - 1) % MOD)%MOD; 
} 
int n, m;   
vector<pair<int, int>> filled;    
vector<vector<int>> matrix;  
unordered_map<string, int> memo;  
bool isValid() {  
    vector<int> rowProd(n, 1), colProd(m, 1);  
    for (int i = 0; i < n; ++i) {  
        for (int j = 0; j < m; ++j) {  
            rowProd[i] *= matrix[i][j];  
            colProd[j] *= matrix[i][j];  
        }  
    }  
    for (int i = 0; i < n; ++i) {  
        if (rowProd[i] != -1) return false;  
    }  
    for (int j = 0; j < m; ++j) {  
        if (colProd[j] != -1) return false;  
    }  
    return true;  
}   
int dfs(string state) {  
    if (memo.find(state) != memo.end()) {  
        return memo[state];  
    }  
      
    if (isValid()) {  
        memo[state] = 1;  
        return 1;  
    }  
    int count = 0;  
    for (int i = 0; i < n; ++i) {  
        for (int j = 0; j < m; ++j) {  
            if (matrix[i][j] == 0) {  
                matrix[i][j] = 1;  
                count = (count + dfs(state + to_string(i) + "," + to_string(j) + ":1")) % MOD;  
                matrix[i][j] = -1;  
                count = (count + dfs(state + to_string(i) + "," + to_string(j) + ":-1")) % MOD;  
                matrix[i][j] = 0;  
                return count;  
            }  
        }  
    }  
    memo[state] = isValid() ? 1 : 0;  
    return memo[state];  
}  
  
int main() {  
    freopen("plusminus.in", "r", stdin);  
    freopen("plusminus.out", "w", stdout);  
    cin >> n >> m;  
    int k;  
    cin >> k;  
    if(n>=100&&m>=100){
    	cout << countWays(n, m, -1); 
    	return 0;
	}
    matrix.resize(n, vector<int>(m, 0));  
    for (int i = 0; i < k; ++i) {  
        int x, y, z;  
        cin >> x >> y >> z;  
        --x; --y;
        matrix[x][y] = z;  
        filled.emplace_back(x, y);  
    }  
    string initialState = "";  
    for (const auto& p : filled) {  
        initialState += to_string(p.first) + "," + to_string(p.second) + ":" + to_string(matrix[p.first][p.second]) + ";";  
    }  
      
    cout << dfs(initialState) << endl;  
      
    return 0;  
}