Dijkstra Algorithm

Input

The first line contains three integers $n$, $s$, and $f$ (1 \leq n \leq 100,\ 1 \leq s, f \leq n), where $n$ is the number of vertices in the graph. Each of the following $n$ lines contains $n$ integers, representing the adjacency matrix of the graph. The integer at the $i$-th row and $j$-th column indicates the weight of the edge from vertex $i$ to vertex $j$. A value of $-1$ means there is no edge between the vertices, while a non-negative value represents the weight of the edge. The main diagonal of the matrix always contains zeros.

Output

Print the shortest distance from vertex $s$ to vertex $f$. If there is no path between the two vertices, print $-1$.

Examples