Untitled

import java.util.*;
import java.io.*;

public class Main {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;
        public FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        String next() {
            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() {
            return Long.parseLong(next());
        }
        double nextDouble() {
            return Double.parseDouble(next());
        }
        String nextLine() {
            String str = "";
            try {
                str = br.readLine().trim();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        }
    }
    static class FastWriter {
        private final BufferedWriter bw;
        public FastWriter() {
            this.bw = new BufferedWriter(new OutputStreamWriter(System.out));
        }
        public void print(Object object) throws IOException {
            bw.append("" + object);
        }
        public void println(Object object) throws IOException {
            print(object);
            bw.append("\n");
        }
        public void close() throws IOException {
            bw.close();
        }
    }
    public static int solve(int[][] matrix) { 
        int maxArea = 0;
        int[] heights = new int[matrix[0].length];
        
        for (int[] row : matrix) { 
            for (int j = 0; j < row.length; j++) { 
                heights[j] = (row[j] == 0) ? 0 : heights[j] + 1;
            }
            maxArea = Math.max(maxArea, largestRectangle(heights));
        }
        return maxArea;
    }
    public static int largestRectangle(int[] heights) { 
        Stack<Integer> stack = new Stack<>();
        int maxArea = 0;
        int index = 0;
        
        while (index < heights.length) { 
            if (stack.isEmpty() || heights[index] >= heights[stack.peek()]) { 
                stack.push(index++);
            } else { 
                int top = stack.pop();
                int width = stack.isEmpty() ? index : index - stack.peek() - 1;
                maxArea = Math.max(maxArea, heights[top] * width);
            }
        }
        while (!stack.isEmpty()) { 
            int top = stack.pop();
            int width = stack.isEmpty() ? heights.length : heights.length - stack.peek() - 1;
            maxArea = Math.max(maxArea, heights[top] * width);
        }
        return maxArea;
    }
    
    public static void main(String[] args) {
        try {
            FastReader sc = new FastReader();
            FastWriter out = new FastWriter();
            int T = sc.nextInt();
            
            for (int i = 0; i < T; i++) { 
                int m = sc.nextInt();
                int n = sc.nextInt();
                int[][] matrix = new int[m][n];
                
                for (int j = 0; j < m; j++) { 
                    for (int k = 0; k < n; k++) { 
                        matrix[j][k] = sc.nextInt();
                    }
                }
                out.println(solve(matrix));
            }
            out.close();
        }
        catch (Exception e) {
            e.printStackTrace();
            return;
        }
    }
}