#include <bits/stdc++.h>

using namespace std;
int T;
int n, m;
const int N = 2 * 1e5 + 10;
vector<int> a[N];
struct Node {
    int x, y;
} wei[N];
vector<int> f[N];
vector<Node> from[N];
int dx[] = {-1, 1, 0, 0}, dy[] = {0, 0, 1, -1};
int ans[N], cnt;
void work() {
    scanf("%d%d", &n, &m);
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            int u;
            scanf("%d", &u);
            a[i].push_back(u);
            f[i].push_back(0);
            from[i].push_back({0, 0});
        }
    }
    // printf("1111\n");
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            wei[a[i][j]] = {i, j};
        }
    }
    // for(int i = 0; i < n * m; i++) printf("%d %d\n", wei[i].x, wei[i].y);
    // printf("1111\n");
    for(int i = n * m - 1; i >= 0; i--) {
        int xx = wei[i].x, yy = wei[i].y;
        for(int k = 0; k < 4; k++) {
            int nx = xx + dx[k], ny = yy + dy[k];
            if(nx < 0 || nx >= n || ny < 0 || ny >= m) continue;
            if(a[nx][ny] < a[xx][yy]) continue;
            // printf("%d %d %d\n", i, nx, ny);
            if(f[xx][yy] < f[nx][ny] + 1) {
                f[xx][yy] = f[nx][ny] + 1;
                from[xx][yy] = {nx, ny};
            } else if(f[xx][yy] == f[nx][ny] + 1 && a[from[xx][yy].x][from[xx][yy].y] > a[nx][ny]) {
                from[xx][yy] = {nx, ny};
            }
        }
    }
    // printf("1111\n");
    int maxn = 0, x = 0, y = 0;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            // printf("%d %d %d %d\n", i, j, from[i][j].x, from[i][j].y);
            // printf("%d ", f[i][j]);
            if(maxn < f[i][j]) {
                maxn = f[i][j];
                x = i, y = j;
            } else if(maxn == f[i][j] && a[x][y] > a[i][j]) x = i, y = j;
        }
        // printf("\n");
    }
    printf("%d\n", maxn + 1);
    cnt = 0;
    while(x != 0 || y != 0 || cnt == 0) {
        printf("%d ", a[x][y]);
        cnt++;
        int xx = x, yy = y;
        x = from[xx][yy].x;
        y = from[xx][yy].y;
    }
    printf("\n");
    // for(int i = cnt; i >= 1; i--) printf("%d ", ans[i]);
    // printf("\n");
    for(int i = 0; i < n; i++) {
        a[i].erase(a[i].begin(), a[i].end());
        f[i].erase(f[i].begin(), f[i].end());
        from[i].erase(from[i].begin(), from[i].end());
    }
}
int main() {
    scanf("%d", &T);
    while(T--) {
        work();
    }
}