/*====Corycle====*/
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int inf = 0x3f3f3f3f;
const int N = 5e5 + 5;
int read() {
    int s = 0, f = 1;
    char c = getchar();
    while (c < '0' || c > '9') {
        if (c == '-')
            f = -1;
        c = getchar();
    }
    while (c >= '0' && c <= '9') {
        s = s * 10 + c - '0';
        c = getchar();
    }
    return s * f;
}
int n, m, cnt, Ans, fa[N];
struct edge {
    int x, y, dist;
} e[N];
inline int id(int x, int y) { return (x - 1) * m + y; }
bool cmp(edge A, edge B) { return A.dist > B.dist; }
int Find(int x) { return x == fa[x] ? x : fa[x] = Find(fa[x]); }
void Kruskal() {
    sort(e + 1, e + cnt + 1, cmp);
    for (int i = 1; i <= n * m; i++) fa[i] = i;
    for (int i = 1; i <= cnt; i++) {
        int x = Find(e[i].x), y = Find(e[i].y);
        if (x == y)
            continue;
        fa[x] = y;
        Ans -= e[i].dist;
    }
}
int main() {
    //	freopen("_.in","r",stdin);
    //	freopen("_.out","w",stdout);
    int T = read();
    while (T--) {
        n = read();
        m = read();
        cnt = Ans = 0;
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                int x = read(), y = read();
                Ans += x + y;
                if (i != n)
                    e[++cnt] = (edge){ id(i, j), id(i + 1, j), x };
                if (j != m)
                    e[++cnt] = (edge){ id(i, j), id(i, j + 1), y };
            }
        }
        Kruskal();
        printf("%d\n", Ans);
    }
    return 0;
}