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

\(1 \le T \le 600000\)
\(1 \le N \le 200000\)
\(0 \le M \le 500000\)
\(\sum N \le 600000\)
\(\sum M \le 1500000\)