import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
import java.util.List;
import java.util.Arrays;
import java.util.ArrayList;
public class Main {
    //Program start
    
    //Program end

    @Test
public void test1() {
    assertEquals(new ArrayList<>(Arrays.asList(new ArrayList<>(Arrays.asList(3,0,0)),new ArrayList<>(Arrays.asList(0,0,1)),new ArrayList<>(Arrays.asList(0,2,0)))), buildMatrix(3, new ArrayList<>(Arrays.asList(new ArrayList<>(Arrays.asList(1,2)),new ArrayList<>(Arrays.asList(3,2)))), new ArrayList<>(Arrays.asList(new ArrayList<>(Arrays.asList(2,1)),new ArrayList<>(Arrays.asList(3,2))))));
}
@Test
public void test2() {
    assertEquals([], buildMatrix(3, new ArrayList<>(Arrays.asList(new ArrayList<>(Arrays.asList(1,2)),new ArrayList<>(Arrays.asList(2,3)),new ArrayList<>(Arrays.asList(3,1)),new ArrayList<>(Arrays.asList(2,3)))), new ArrayList<>(Arrays.asList(new ArrayList<>(Arrays.asList(2,1))))));
}

}