#include<bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
/*#pragma GCC target("sse,sse2,sse3,ssse3,sse4,avx,avx2")*/
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#define INF 999999999999999999
#define pb push_back
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
#define ff first
#define ss second 
#define printclock cerr<<"Time : "<<1000*(long double)clock()/(long double)CLOCKS_PER_SEC<<"ms\n";
#define ll long long
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll B) { return (unsigned ll)rng() % B;}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
int main() {
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    fast;
    ll _T = 1;
    
    cin >> _T;
    while (_T--) {
        ll n, m;
        cin >> n >> m;
        vector<vector<ll>> v(n, vector<ll>(m));
        for(int i = 0; i < n; i++){
            for(int j = 0; j < m; j++){
                ll x;
                cin >> x;
                v[i][j] = x;
            }
        }
        ll lo = 0, hi = n + m - 2;
        ll ans = 0;
        while(lo <= hi){
            ll mid = (lo + hi) / 2;
            bool flag = true;
            ll y = -1, cnt = 0;
            for(int i = 0; i < n; i++){
                for(int j = 0; j < m; j++){
                    if(v[i][j] <= lo){
                        if(y > j){
                            flag = false;
                        }
                        else{
                            y = j;
                        }
                    }   
                }
            }
            if(flag){
                lo = mid + 1;
                ans = mid + 1;
            }
            else{
                hi = mid - 1;
            }
        }
        cout << ans << "\n";
    }
    return 0;
}