#include <cstdio>

#define max(x, y) ((x) > (y) ? (x) : (y))

#define N 505

int t, n, g[N][N], lowcost[N], used[N], ans;

void prim(){

    for(int i = ; i <= n; i++){

        lowcost[i] = g[][i];

        used[i] = ;

    }

    used[] = ;

    ans = ;

    for(int i = ; i <= n; i++){

        int j=;

        while(used[j]) j++;

        for(int k = ; k <= n; k++)

            if(!used[k] && lowcost[k] < lowcost[j])

                j = k;

        ans = max(ans, lowcost[j]);

        used[j] = ;

        for(int k = ; k <= n; k++)

            if(!used[k] && g[j][k] < lowcost[k])

                lowcost[k] = g[j][k];

    }

}

int main(){

    scanf("%d", &t);

    while(t--){

        scanf("%d", &n);

        for(int i = ; i <= n; i++)

            for(int j = ; j <= n; j++)

                scanf("%d", &g[i][j]);

        prim();

        printf("%d\n", ans);

    }

    return ;

}