B

#include <bits/stdc++.h>

using namespace std;

#define ll     long long
#define _test   int _TEST; cin>>_TEST; while(_TEST--)

int main()
{
    _test
    {
        int n;
        cin>>n;

        int ans;
        int x = 0;
        for(int i=0; i<n; i++)
        {
            int a, b;
            cin>>a>>b;

            if(a > 10)      continue;

            if(b > x)
            {
                x = b;
                ans = i+1;
            }
        }

        cout<<ans<<"\n";
    }
}