import java.util.*;
import java.io.*;
import java.math.*;
import java.util.regex.Pattern;

class Main{

    static void solve(){

        int h = ni(), w = ni(), k = ni();
        long [][] value = new long[h][w];
        while(k-->0) {
            int x = ni(), y = ni();
            long v = nl();
            x--;y--;
            value[x][y] = v;
        }
        long answer = 0;
        for(int i=0;i<h;i++) {
            for(int j=0;j<w;j++) {
                for(int x=0;x<h;x++) {
                    for(int y=0;y<w;y++) {
                        if(x + y >= i + j && x - y >= i - j) {
                            answer += (value[x][y] % MOD);
                        }
                    }
                }
            }
        }
        output.println(answer);
    }

    /* 関数 */



    /* 定数 */

    static PrintWriter output;
    static Scanner sc;
    static int  Inf = 1010101010; 
    static long Lnf = (long)1e18;
    static final long mod = 1000000007;
    static final long MOD = 998244353 ;

    /* 長いやつ  */

    static String cut(String S , int start, int end) { return S.substring(start,end);}
    static char cut(String S , int start) { return S.charAt(start);}
    static String tos(int val) { return Integer.toString(val);}
    static String tos(long val) { return Long.toString(val);}
    static int toi(String S) { return Integer.parseInt(S);}
    static long tol(String S) { return Long.parseLong(S);}

    /* 実装が面倒なやつ */

    public static long factorial(long n){
        return n <= 0 ? 1 : n * factorial(n-1);
    }

    public static int digits(long n) {
        return String.valueOf(n).length();
    }

    static boolean kaibun(String S) {
        StringBuilder s = new StringBuilder();
        s.append(S);
        return s.reverse().toString().equals(S);
    }

    static boolean isNumber(String value) {
        boolean result = false;
        if (value != null) {
            Pattern pattern = Pattern.compile("^[0-9]+$|-[0-9]+$");
            result = pattern.matcher(value).matches();
        }
        return result;
    }

    static Map<Integer,Integer> counter(int [] A) {
        HashMap<Integer,Integer> count = new HashMap<>();
        for(int i=0;i<A.length;i++) {
            if(!count.containsKey(A[i])) count.put(A[i],1);
            else count.put(A[i],count.get(A[i])+1);
        }
        return count;
    }

    static Map<Long,Integer> counter(long [] A) {
        HashMap<Long,Integer> count = new HashMap<>();
        for(int i=0;i<A.length;i++) {
            if(!count.containsKey(A[i])) count.put(A[i],1);
            else count.put(A[i],count.get(A[i])+1);
        }
        return count;
    }

    /*入出力端折るやつ*/

    static int ni(){ return Integer.parseInt(sc.next());}
    static long nl(){ return Long.parseLong(sc.next());}
    static double nd(){ return Double.parseDouble(sc.next());}
    static String ns(){ return sc.next();}
    static BigInteger bi(){ return sc.nextBigInteger();}
    static BigDecimal bd(){ return sc.nextBigDecimal();}
    
    static int [] IntArray(int n) {
        int [] Array = new int[n];
        for(int i=0;i<n;i++) Array[i] = ni();
        return Array;
    }
    static int [][] IntArray(int n , int m) {
        int [][] Array = new int[n][m];
        for(int i=0;i<n;i++) for(int j=0;j<m;j++) Array[i][j] = ni();
        return Array;
    }
    static long [] LongArray(int n) {
        long [] Array = new long[n];
        for(int i=0;i<n;i++) Array[i] = nl();
        return Array;
    }
    static long [][] LongArray(int n , int m) {
        long [][] Array = new long[n][m];
        for(int i=0;i<n;i++) for(int j=0;j<m;j++) Array[i][j] = nl();
        return Array;
    }
    static double [] DoubleArray(int n) {
        double [] Array = new double[n];
        for(int i=0;i<n;i++) Array[i] = nd();
        return Array;
    }
    static double [][] DoubleArray(int n , int m) {
        double [][] Array = new double[n][m];
        for(int i=0;i<n;i++) for(int j=0;j<m;j++) Array[i][j] = nd();
        return Array;
    }
    static String [] StringArray(int n) {
        String [] Array = new String[n];
        for(int i=0;i<n;i++) Array[i] = ns();
        return Array;
    }
    static String [][] StringArray(int n , int m) {
        String [][] Array = new String[n][m];
        for(int i=0;i<n;i++) for(int j=0;j<m;j++) Array[i][j] = ns();
        return Array;
    }
    static char [] CharArray(int n) {
        char [] Array = new char[n];
        String S = ns();
        for(int i=0;i<n;i++) Array[i] = S.charAt(i);
        return Array;
    }
    static char [][] CharArray(int n,int m) {
        char [][] Array = new char[n][m];
        for(int i=0;i<n;i++) {
            String S = ns();
            for(int j=0;j<m;j++) Array[i][j] = S.charAt(j);
        }
        return Array;
    }
    static void PrintArray(int [] A) {
        for(int i=0;i<A.length;i++) output.print(A[i]+" ");
        output.println();
    }
    static void PrintArray(long [] A) {
        for(int i=0;i<A.length;i++) output.print(A[i]+" ");
        output.println();
    }
    static void PrintArray(double [] A) {
        for(int i=0;i<A.length;i++) output.print(A[i]+" ");
        output.println();
    }
    static void PrintArray(boolean [] A) {
        for(int i=0;i<A.length;i++) output.print(A[i]+" ");
        output.println();
    }
    static void PrintArray(int [][] A) {
        for(int i=0;i<A.length;i++) {
            for(int j=0;j<A[i].length;j++) {
                if(A[i][j] == Inf) output.print("X ");
                else output.print(A[i][j]+" ");
            }
            output.println();
        }
    }
    static void PrintArray(long [][] A) {
        for(int i=0;i<A.length;i++) {
            for(int j=0;j<A[i].length;j++) {
                if(A[i][j] == Lnf) output.print("X ");
                else output.print(A[i][j]+" ");
            }
            output.println();
        }
    }
    static void PrintArray(boolean [][] A) {
        for(int i=0;i<A.length;i++) {
            for(int j=0;j<A[i].length;j++) {
                output.print(A[i][j]?"O":"X");
            }
            output.println();
        }
    }
    public static void main(String[] args){
        output = new PrintWriter(System.out);
        sc = new Scanner(System.in);
        solve();
        output.flush();
    }
}