You are given a network of directed graph of $N$ vertices and $M$ edges, where every edges' capacity is $1$. An ordered pair $(u, v), u\not=v$ is good, if the maxflow is exactly $1$ upon setting $u$ as the source vertex and $v$ as the sink vertex of the flow network. Find out if all of the ordered pairs $(u, v), u \not= v$ are good or not.

Note

• For ordered pairs, if $x \not=y,$ then $(x, y) \not= (y, x)$.
• Flow Network

Input format

• First line: An integer $T$ - number of testcases.
• Each test case's-
  • First line: Two integers $N, M$.
  • $i$-th of the next $M$ lines: two integers $u_i, v_i$- a directed edge from $u_i$ to $v_i$.

Output format

Print $T$ lines- $i$-th line contains answer for $i$-th testcase. For a testcase, the answer is "Yes" if every ordered pair is good, "No" otherwise.

Constraints

• $1 \le T \le 600000$
• $1 \le N \le 200000$
• $0 \le M \le 500000$
• $\sum N \le 600000$
• $\sum M \le 1500000$