int ret = -1;

while (changed) {

ret++;

changed = false;

fill_n(&tf[0][0], 55 * 55, false);

for (int i = 0; i <= n; i++)

for (int j = 0; j <= n; j++) {

if (tf[i][j])

continue;

v.clear();

sum = 0, num=0;

for (int k = 0; k < 4; k++) {

int ny = i + dy[k], nx = j + dx[k];

int interval = abs(map[i][j] - map[ny][nx]);

if (low <= interval && interval <= high) {

num++;

tf[i][j] = true;

sum += map[i][j];

v.push_back({ i,j });

break;

}

}

for (int vi = 0; vi < v.size(); vi++) {

pair<int, int> cur = v[vi];

for (int k = 0; k < 4; k++) {

int ny = cur.first + dy[k], nx = cur.second + dx[k];

int interval = abs(map[cur.first][cur.second] - map[ny][nx]);

if (low <= interval && interval <= high) {

if (!tf[ny][nx]) {

num++;

tf[ny][nx] = true;

sum += map[ny][nx];

v.push_back({ ny,nx });

}

}

}

}

if (sum == 0)

continue;

else {

changed = true;

for (int i = 0; i < v.size(); i++)

map[v[i].first][v[i].second] = sum / num;

}

}

}

return ret;

{

fill_n(&map[0][0], 55 * 55, 999);

scanf("%d %d %d", &n, &low, &high);

for (int i = 1; i <= n; i++)

for (int j = 1; j <= n; j++)

scanf("%d", &map[i][j]);

printf("%d",bfs());

return 0;