A tournament has *N* teams with multiple rounds(N = 2^k where k >=1). Schedule the tournament with the following constraints:

- Every team plays once and only once in a round
- Every team plays every other team only once in the whole tournament

Example:

N = 4

Teams: 1, 2, 3, 4

Round 1: 1-2, 3-4

Round 2: 1-3, 2-4

Round 3: 1-4, 2-3