#include<bits/stdc++.h>
#define Gc() getchar() 
#define Me(x,y) memset(x,y,sizeof(x))
#define Mc(x,y) memcpy(x,y,sizeof(x))
#define d(x,y) ((m)*(x-1)+(y))
#define R(n) (rnd()%(n)+1)
#define Pc(x) putchar(x)
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
using namespace std;using ll=long long;using db=double;using lb=long db;using ui=unsigned;using ull=unsigned long long;using pii=pair<int,int>;using LL=__int128;
const int N=1e5+5,M=1e5,K=600+5,mod=1e9+7,Mod=mod-1;const db eps=1e-6;const ll INF=1e18+7;mt19937 rnd(263082);
int n,m,g[N];vector<int> S[N],w[N];
namespace BIT{
	int f[N];void Cl(){fill(f+1,f+n+1,0);}
	void add(int x,int w){while(x) f[x]=max(f[x],w),x-=x&-x;}
	int qry(int x){int ans=0;while(x<=n) ans=max(ans,f[x]),x+=x&-x;return ans;}
}
void Solve(){
	int i,j;scanf("%d%d",&n,&m);
	for(i=1;i<=n;i++) S[i].clear();
	while(m--) {
		int x,y;scanf("%d%d",&x,&y);if(x>y) swap(x,y);if(x^y) S[y].emplace_back(x);
	}
	BIT::Cl();
	int ans=0;
	for(i=1;i<=n;i++){
		w[i].clear();
		for(int j:S[i]) {
			int pw=max(g[j],BIT::qry(j))+1;
			w[i].emplace_back(pw);g[i]=max(g[i],pw);
		}
		g[i]=max(g[i-1],g[i]);ans=max(ans,g[i]);
		for(int j=0;j<S[i].size();j++) BIT::add(j,S[i][j]);
	}
	printf("%d\n",n-1-ans);
}
int main(){
	int t=1;
	scanf("%d",&t);
	while(t--) Solve();
	cerr<<clock()*1.0/CLOCKS_PER_SEC<<'\n';
}