Problem Statement
Given is a simple undirected graph with $N$ vertices and $M$ edges. The vertices are numbered $1, \cdots, N$, and the $i$-th edge connects Vertices $a_i$ and $b_i$. Also given is a sequence of positive integers: $c_1, c_2, \cdots, c_N$.
Convert this graph into a directed graph that satisfies the condition below, that is, for each $i$, delete the undirected edge $(a_i, b_i)$ and add one of the two direted edges $a_i \to b_i$ and $b_i \to a_i$.
- For every
$i = 1, 2, \cdots, N$, there are exactly$c_i$vertices reachable from Vertex$i$(by traversing some number of directed edges), including Vertex$i$itself.
In this problem, it is guaranteed that the given input always has a solution.
Constraints
$1 \leq N \leq 100$$0 \leq M \leq \frac{N(N - 1)}{2}$$1 \leq a_i, b_i \leq N$- The given graph has no self-loops and no multi-edges.
$1 \leq c_i \leq N$- There always exists a valid solution.
Input
Input is given from Standard Input in the following format:
N M
a_1 b_1
:
a_M b_M
c_1 c_2 ... c_N
Output
Print $M$ lines.
To add the edge $a_i \to b_i$ for the $i$-th edge, print -> in the $i$-th line; to add the edge $b_i \to a_i$ for the $i$-th edge, print <-.
If there are multiple solutions, any of them will be accepted.
样例
3 3
1 2
2 3
3 1
3 3 3
->
->
->
3 2
1 2
2 3
1 2 3
<-
<-
6 3
1 2
4 3
5 6
1 2 1 2 2 1
<-
->
->
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