// what is matter? never mind. 
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,sse4,popcnt,abm,mmx,avx,avx2")
#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rep(i,a,b) for(int i=(a);i>=(b);--i)
#define ll __uint128_t
//#define ll __int128
//#define ull unsigned long long
#define int long long
#define SZ(x) ((int)((x).size()))
#define ALL(x) (x).begin(),(x).end()
using namespace std;
inline int read()
{
	char c=getchar();int x=0;bool f=0;
	for(;!isdigit(c);c=getchar())f^=!(c^45);
	for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
	return f?-x:x;
}

#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int,int>pii;
typedef vector<int>vi;

#define maxn 500005
#define inf 0x3f3f3f3f

int n,m;
vi e[maxn];

namespace TT{

vi e[maxn],g[maxn],dom[maxn];
int fa[maxn],dfn[maxn],que[maxn],idx;
void adde(int u,int v){e[u].pb(v);}
void dfs(int u){
	que[dfn[u]=++idx]=u;
	for(int v:e[u]){
		if(!dfn[v])dfs(v),fa[dfn[v]]=dfn[u];
		g[dfn[v]].pb(dfn[u]);
	}
}
int p[maxn],mn[maxn],sdom[maxn],idom[maxn];
int get(int u){
	if(p[u]!=p[p[u]]){
		if(sdom[mn[u]]>sdom[get(p[u])])mn[u]=get(p[u]);
		p[u]=p[p[u]];
	}return mn[u];
} 
void solve()
{
	For(i,1,n)p[i]=mn[i]=sdom[i]=i;
	dfs(1);
	Rep(i,n,2){
		for(int j:g[i])sdom[i]=min(sdom[i],sdom[get(j)]);
		dom[sdom[i]].pb(i);
		int x=p[i]=fa[i];
		for(int j:dom[x])idom[j]=(sdom[get(j)]<x?get(j):x);
		dom[x].clear();
	}
	For(i,2,n){
		if(idom[i]!=sdom[i])idom[i]=idom[idom[i]];
		::e[que[idom[i]]].pb(que[i]);
	}
}
void init(){
	For(i,1,n) e[i].clear(),g[i].clera(),dom[i].clear(),fa[i]=dfn[i]=que[i]=p[i]=mn[i]=sdom[i]=idom[i]=0; idx=0;
	For(i,1,m){
		int u=read(),v=read();
		e[v].pb(u);
	}
	solve();
}
}

void dfs()

void work()
{
	n=read(),m=read();
	TT::init();
	
}

signed main()
{
	int T=read();
	while(T--)work();
	return 0;
}
/*

*/

answer.code: In function ‘void TT::init()’:
answer.code:72:38: error: ‘vi’ {aka ‘class std::vector<long long int>’} has no member named ‘clera’; did you mean ‘clear’?
   72 |         For(i,1,n) e[i].clear(),g[i].clera(),dom[i].clear(),fa[i]=dfn[i]=que[i]=p[i]=mn[i]=sdom[i]=idom[i]=0; idx=0;
      |                                      ^~~~~
      |                                      clear
answer.code: At global scope:
answer.code:83:1: error: expected initializer before ‘void’
   83 | void work()
      | ^~~~
answer.code: In function ‘int main()’:
answer.code:93:19: error: ‘work’ was not declared in this scope
   93 |         while(T--)work();
      |                   ^~~~