Problems

# Floyd

# Floyd

Given a directed weighted graph. Find a pair of vertices, the shortest distance from one of them to another is maximum among all pairs of vertices.

## Input data

The first line contains the number of vertices n (1 ≤ n ≤ 100). The next n lines of n numbers describe the weighted matrix. Here -1 means no edges between vertices, and any non-negative number - the presence of an edge of given weight. All elements on the main diagonal are always zero.

## Output data

Print the desired maximum shortest distance.

## Examples

Input example #1

4 0 5 9 -1 -1 0 2 8 -1 -1 0 7 4 -1 -1 0

Output example #1

16