//poj 2485 还是先用prime,写起来比较快 题意是问最小生成树的最大边
#include <iostream>
#include <algorithm>
#define inf 65537
using namespace std;
int weight[501][501];
int dist[501];
bool mark[501];
int max1;
int prime(int n)
{
dist[0] = 0;
mark[0] = true;
for(int i =1; i < n; i++)
{
dist[i] = weight[0][i];
}
for(int i = 1; i < n; i++)
{
int min1 = inf;
int minIndex = -1;
for(int j = 1; j < n; j++)
{
if(!mark[j] && dist[j] < min1)
{
min1 = dist[j];
minIndex = j;
}
}
if(min1 > max1)
max1 = min1;
dist[minIndex] = 0;
mark[minIndex] = true;
for(int j = 1; j < n; j++)
if(!mark[j])
dist[j] = (weight[minIndex][j] < dist[j])?weight[minIndex][j]:dist[j];
}
return max1;
}
int main()
{
int t;
cin>>t;
while(t--)
{
memset(weight, 0, sizeof(weight));
memset(dist, 0, sizeof(dist));
memset(mark, 0, sizeof(mark));
int n;
cin>>n;
for(int i = 0; i < n; i++)
{
for(int j = 0; j < n; j++)
{
cin>>weight[i][j];
}
}
max1 = 0;
cout<<prime(n)<<endl;
}
return 0;
}