题解 | #矩阵计算#

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        int m = scan.nextInt();
        int[][] arr = new int[n][m];
        int sum = 0;
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr[i].length; j++) {
                arr[i][j] = scan.nextInt();
                if (arr[i][j] > 0) {
                    sum += arr[i][j];
                }
            }
        }
        System.out.println(sum);
    }
}