Untitled

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;

public class _11_ReverseMatrixDiagonals {

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        int[] dimensions = Arrays.stream(reader.readLine().split("\\s+"))
                .mapToInt(Integer::parseInt)
                .toArray();

        int rows = dimensions[0];
        int cols = dimensions[1];

        int[][] matrix = new int[rows][cols];

        for (int i = 0; i < rows; i++) {
            matrix[i] = Arrays.stream(reader.readLine().split("\\s+"))
                    .mapToInt(Integer::parseInt)
                    .toArray();
        }

        int row = rows - 1;
        int col = cols - 1;

        while (row >= 0) {
            int r = row;
            int c = col;
            while (c < cols && r >= 0) {
                System.out.print(matrix[r--][c++] + " ");
            }
            System.out.println();
            col--;
            if (col < 0) {
                col = 0;
                row--;
            }
        }
    }
}