Chess Tournament
Huseyn loves to watch chess. And his favorite Candidates Tournament will have N players. The tournament runs in a round robin format, so N(N-1)/2* games will be played. Is it possible to organize the scheduling of these parties so as to meet certain conditions?
Each player must play at least one game a day.
Each i - th player (1 <= i <= N) plays one game against player
A[i][1],A[i][2]....,A [i][N-1]in this queue
If so, find the minimum number of days you need.
####Input dataThe first line contains number N (3 ≤ N ≤ 1000), the number of players.The next N lines contain N-1 numbers A[i][j].
####OutputIf it is possible to schedule all matches so that all conditions arecompleted, output the minimum number of days that is required;if this is not possible, print -1.
Explanations:
In the first test, all conditions can be met if matches are scheduled for three days as follows:
Day 1: Player 1 vs. Player 2
Day 2: Player 1 vs. Player 3
Day 3: Player 2 vs. Player 3This is the minimum number of days required.
In the third test, any match planning violates some conditions.