#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 = 200+9;const ll MOD = 1e9 + 7;
vector<ll> s[Q];
vector<ll> x[Q];
ll ans[Q];
ll  vis[Q];
void dfs(ll now){
    if(vis[now]) return;
    vis[now]=true;
    for(auto i:s[now]){
        ans[i]=ans[now]-1;
        dfs(i);
    }
}
void dfs2(ll now){
    if(vis[now]) return;
    vis[now]=true;
    for(auto i:x[now]){
        ans[i]=ans[now]+1;
        dfs2(i);
    }
}
void solve(){
   ll n,m;cin>>n>>m;
   bool ok=true;
   for (ll i = 1; i <= n; i++)
   {
    ans[i]=0;
   }
   
   for (ll i = 1; i <= m; i++)
   {
    ll o,p;cin>>o>>p;
    if(o==p) ok=false;
    x[o].push_back(p);
    s[p].push_back(o);
   }
   if(ok==false){
    for (ll i = 1; i <= n; i++)
    {
        cout<<0;
    }cout<<"\n";
    return;
   }
   ans[1]=1000;
   for (ll i = 1; i <= n; i++)
   {
    if(ans[i]!=0){
        memset(vis,0,sizeof vis);
        dfs(i);
        memset(vis,0,sizeof vis);
        dfs2(i);
    }
   }
   vector<ll> v;v.push_back(0);
   for (ll i = 1; i <= n; i++)
   {
        v.push_back(ans[i]);
        if(ans[i]==0){
            for (ll i = 1; i <= n; i++)
            {
                cout<<0;
            }cout<<"\n";
                return;
        }
        x[i].clear();
        s[i].clear();
   }
   ll t[1000];
   memset(t,0,sizeof t);
   sort(v.begin()+1,v.end());
    for (ll i = 1; i <= n; i++)
    {
        if(ans[i]==v[(n+1)/2]){
            t[i]=1;
            break;
        }
    }
    for (ll i = 1; i <= n; i++)
    {
        cout<<t[i];
    }
    cout<<"\n";
   

}
int main(){
    ios;ll _=1;cin>>_;
    while (_--)solve();
    return 0;
}