#D12342. Coloring Edges
Coloring Edges
Coloring Edges
You are given a directed graph with n vertices and m directed edges without self-loops or multiple edges.
Let's denote the k-coloring of a digraph as following: you color each edge in one of k colors. The k-coloring is good if and only if there no cycle formed by edges of same color.
Find a good k-coloring of given digraph with minimum possible k.
Input
The first line contains two integers n and m (2 ≤ n ≤ 5000, 1 ≤ m ≤ 5000) — the number of vertices and edges in the digraph, respectively.
Next m lines contain description of edges — one per line. Each edge is a pair of integers u and v (1 ≤ u, v ≤ n, u ≠ v) — there is directed edge from u to v in the graph.
It is guaranteed that each ordered pair (u, v) appears in the list of edges at most once.
Output
In the first line print single integer k — the number of used colors in a good k-coloring of given graph.
In the second line print m integers c_1, c_2, ..., c_m (1 ≤ c_i ≤ k), where c_i is a color of the i-th edge (in order as they are given in the input).
If there are multiple answers print any of them (you still have to minimize k).
Examples
Input
4 5 1 2 1 3 3 4 2 4 1 4
Output
1 1 1 1 1 1
Input
3 3 1 2 2 3 3 1
Output
2 1 1 2
inputFormat
Input
The first line contains two integers n and m (2 ≤ n ≤ 5000, 1 ≤ m ≤ 5000) — the number of vertices and edges in the digraph, respectively.
Next m lines contain description of edges — one per line. Each edge is a pair of integers u and v (1 ≤ u, v ≤ n, u ≠ v) — there is directed edge from u to v in the graph.
It is guaranteed that each ordered pair (u, v) appears in the list of edges at most once.
outputFormat
Output
In the first line print single integer k — the number of used colors in a good k-coloring of given graph.
In the second line print m integers c_1, c_2, ..., c_m (1 ≤ c_i ≤ k), where c_i is a color of the i-th edge (in order as they are given in the input).
If there are multiple answers print any of them (you still have to minimize k).
Examples
Input
4 5 1 2 1 3 3 4 2 4 1 4
Output
1 1 1 1 1 1
Input
3 3 1 2 2 3 3 1
Output
2 1 1 2
样例
3 3
1 2
2 3
3 1
2
1 1 2
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