import java.util.*;
public class MyClass {

    public static int end(int[] in) {
        return in[1];
    }

    public static int start(int[] in) {
        return in[0];
    }

    public static void main(String args[]) {
        List<int[]> A = Arrays.asList(new int[]{0, 2}, new int[]{5, 10}, new int[]{16, 20});
        List<int[]> B = Arrays.asList(new int[]{1, 5}, new int[]{10, 18}, new int[]{20, 23});

        List<int[]> res = new ArrayList<int[]>();

        int a=0, b=0;

        while( a < A.size() && b < B.size() && ( end(A.get(a)) <= end(B.get(b)) || end(B.get(b)) <= end(A.get(a)))) {
            int x = Math.max(start(A.get(a)), start(B.get(b)));
            int y = Math.min(end(A.get(a)), end(B.get(b)));

            int[] temp = new int[]{0, 0};
            temp[0] = x;
            temp[1] = y;

            res.add(temp);

            if( end(A.get(a)) < end(B.get(b))) {
                a++;
            } else {
                b++;
            }
        }

        for(int[] i : res) {
            System.out.print(i[0] + ",");
            System.out.print(i[1] + ",");
            System.out.println(" ");
        }
    }

}