input:

7
1 4
4 0
2 3
3 1
3 5
0 0
2 4

output:

0 1 1
0 0
1 2 4
4 0
2 3 5
3 5
3 0 8
1 4
9

result:

wrong answer 1st numbers differ - expected: '9', found: '0'