public int CompareTo(Object obj)
{
RING r = (RING)obj;
if (this.r1 != r.r1)
{
return(this.r1.CompareTo(r.r1));
}
return(this.r2.CompareTo(r.r2));
}
static void Run()
{
int t = int.Parse(Console.ReadLine());
while (t > 0)
{
int n = int.Parse(Console.ReadLine());
RING[] rings = new RING[n];
for (int i = 0; i < n; i++)
{
string[] strCircle = Console.ReadLine().Split();
int innerRadius = int.Parse(strCircle[0]);
int outerRadius = int.Parse(strCircle[1]);
rings[i].r1 = innerRadius;
rings[i].r2 = outerRadius;
rings[i].Id = i + 1;
}
Array.Sort(rings);
bool isPossible = true;
for (int i = n - 2; i >= 0; i--)
{
if (rings[n - 1].r1 <= rings[i].r2)
{
isPossible = false;
break;
}
}
if (isPossible)
{
Console.WriteLine(rings[n - 1].Id);
}
else
{
Console.WriteLine(-1);
}
t--;
}
}