HomeVolumesContestsSectionsForumsUsersPrintHelpAbout

Volumes > Camp. Turkey > problem:


Diameter of graph

Volume problems

• Divisors count
• GCD of ones
• Set cover problem
• Subsets
• The N Queens Problem
• Maximum Sum 2
• Gifts of Santa Claus
• Shopping
• Diameter of graph
• Corridor
• Prime numbers
• Rectangles on a plane
• Divisors

Feedback

If you notice incorrect translations in Contester, please let author know.

Time limit 1000/1000/1000/1000 ms. Memory limit 65000/65000/65000/65000 Kb.

Problem description

Given a connected weighted graph with N vertices. A diameter of graph is maximum of shortest distances between any 2 vertices. Find diameter of given graph.

Input

There is a single integer N on the first line (1 ≤ N ≤ 100). There are N integers on each of N next lines. Where (i, j) = -1 if cities i and j are not connected, and any nonnegative integer not bigger than 1000 which denotes distance between i and j.

Output

Write maximum of shortest distances between 2 vertices.

Example

stdin stdout

4
0 -1 1 2
-1 0 -1 5
1 -1 0 4
2 5 4 0

8

Для отправки решений необходимо выполнить вход.

www.contester.ru