It was a dark and dreary Christmas Eve when our hero pondered, weak and weary,
over a quaint and curious COCI task. When he nodded, nearly napping, suddenly
he heard a tapping, tapping and a mighty roar. A giant reindeer broke through his
chamber door, merely this and nothing more. While our hero’s heart slightly fluttered,
the beast simply uttered: “I won’t leave until you solve this problem”.
In the problem you were given two integers \(N\) and \(M\) and you were supposed to
perfectly match the numbers from sets \(A\) = {0, 1, 2, . . . , \(N - 1\)} and \(B\) = {M, . . . , M +
\(N - 1\)} into \(N\) pairs, such that for the matched numbers \(x\) ∈\(A\) and \(y\) ∈\(B\) it holds
\(x\) & \(y = x\), where & denotes a bitwise AND operation.

Subtask
Score
Constraints
1
10
\(N\) is a power of 2
2
29
\(N + M\) is a power of 2
3
39
\(N + M \le 1000\)
4
32
No additional constraints.

The first line contains two integers \(N\) and \(M\) (\(1 \le N \le M\), \(N + M \le 10^{6}\)) from the task description.

You should output \(N\) lines and in each line you should output two integers \(x\) and \(y\), where \(x\) belongs to
set \(A\) and \(y\) belongs to set \(B\). Numbers in each line should correspond to one of the matched pairs from
task description.
It is possible to prove that the solution always exists.

생성자가 기록되지 않았습니다.

출처 COCI 2019/2020 Contest 3