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Volumes > C. T. 2011 > problem:


Dijkstra

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• Dijkstra
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• Coin Game
• Cow PinBall
• Cow Sorting
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• Connected components

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Time limit 1000/1000/4000/4000 ms. Memory limit 65000/65000/65000/65000 Kb.

Problem description

Find the shortest path from vertex S to F in directed weighted graph.

Input

Line 1: Three integers: N - number of vertices, S - starting vertex, F - destination vertex (1 ≤ S, F ≤ N ≤ 100).

Line 2..N+1: Adjacency matrix, where -1 - means no edge, a[i][j] = 0 when i=j, all other positive integers ≤ 1000 are weights of edges.

Output

Write distance from S to F or -1 if there is no path.

Example

stdin stdout

3 1 2
0 -1 2
3 0 -1
-1 4 0

6

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