Problem Statement
You are given a directed graph with $N$ vertices and $M$ edges. The vertices are numbered $1, 2, ..., N$, and the edges are numbered $1, 2, ..., M$. Edge $i$ points from Vertex $a_i$ to Vertex $b_i$.
For each edge, determine whether the reversion of that edge would change the number of the strongly connected components in the graph.
Here, the reversion of Edge $i$ means deleting Edge $i$ and then adding a new edge that points from Vertex $b_i$ to Vertex $a_i$.
Constraints
$2 \leq N \leq 1000$$1 \leq M \leq 200,000$$1 \leq a_i, b_i \leq N$$a_i \neq b_i$- If
$i \neq j$, then$a_i \neq a_j$or$b_i \neq b_j$.
Input
Input is given from Standard Input in the following format:
N M
a_1 b_1
a_2 b_2
:
a_M b_M
Output
Print $M$ lines. In the $i$-th line, if the reversion of Edge $i$ would change the number of the strongly connected components in the graph, print diff; if it would not, print same.
样例
3 3
1 2
1 3
2 3
same
diff
same
2 2
1 2
2 1
diff
diff
5 9
3 2
3 1
4 1
4 2
3 5
5 3
3 4
1 2
2 5
same
same
same
same
same
diff
diff
diff
diff
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