#include<bits/stdc++.h>
#define ios ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
using namespace std;using ll = long long;using PLL = pair<ll,ll>;
const ll MAX = 1e18;const ll MIN = -1e18;const ll INF=0x3f3f3f3f;
const ll Q = 2e6+9;const ll MOD = 1e9 + 7;
set<ll> d[Q];ll ans;
bool vis[Q];ll n,m;
ll now=1;
void dfs(ll x){
    for(auto i:d[x]){
        if(i<now+1) continue;
        if(i>now+1) break;
        if(i==now+1)
        {
            now++;
            dfs(now);
        }
    }
    if(now<n and x==1){
        ans++;
        d[now].insert(now+1);
        now=1;
        dfs(1);
    }
}
void solve(){
   cin>>n>>m;
   memset(vis,0,sizeof vis);
   ans=0;now=1;
   for (ll i = 0; i <= n; i++) d[i].clear();
   for (ll i = 0; i < m; i++)
   {
    ll o,p;cin>>o>>p;
    if(p>o) d[o].insert(p);
   }
   dfs(1);
   
   cout<<ans<<"\n";
}
int main(){
    ios;ll _=1;cin>>_;
    while (_--)solve();
    return 0;
}