#include <bits/stdc++.h>
#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define i64 long long
#define endl '\n'
#define lb(x) ((x) & (-x))
using namespace std;
const i64 mod = 1e15+7;
const int maxn = 1e3+10;
signed main()
{
    IOS;
    int t; cin >> t;
    while(t--)
    {
        int n,m; cin >> n >> m;
        vector<int> deg(n+1);
        vector<vector<int>> l(n+1),r(n+1);
        for(int i = 1; i <= m; ++i)
        {
            int x,y; cin >> x >> y;
            l[x].push_back(y);
            deg[y]++;
            r[y].push_back(x);
        }
        queue<int> q;
        for(int i = 1; i <= n; ++i) if(deg[i] == 0) q.push(i);
        int ans = 0;
        while(q.size())
        {
            int x = q.front();
            q.pop();
            ans++;
            for(auto it : l[x])
            {
                deg[it]--;
                if(deg[it] == 0) q.push(it);
            }
        }
        if(ans != n)
        {
            for(int i = 0; i < n; ++i) cout << 0;
            cout << endl;
        }
        else
        {
            vector<int> lcnt(n+1),rcnt(n+1);
            vector<int> vis(n+1);

            auto dfsl = [&](auto self,int x) -> void
            {
                if(vis[x]) return;
                vis[x] = 1;
                for(int &u : l[x]) self(self,u);
            };

            auto dfsr = [&](auto self,int x) -> void
            {
                if(vis[x]) return;
                vis[x] = 1;
                for(int &u : r[x]) self(self,u);
            };
            for(int i = 1; i <= n; ++i)
            {
                fill(vis.begin(),vis.end(),0);
                dfsl(dfsl,i);
                for(int j = 1; j <= n; ++j) lcnt[i] += vis[j];
                lcnt[i]--;
            }
            for(int i = 1; i <= n; ++i)
            {
                fill(vis.begin(),vis.end(),0);
                dfsr(dfsr,i);
                for(int j = 1; j <= n; ++j) rcnt[i] += vis[j];
                rcnt[i]--;
            }

            for(int i = 1; i <= n; ++i)
            {
                if(lcnt[i] <= n/2 && rcnt[i] <= n/2) cout << 1;
                else cout << 0;
            }
            cout << endl;
        }
    }
    return 0;
}