1 #include <cmath>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <iostream>
 5 #include <algorithm>
 6 using namespace std;
 7 int num[1100][1100],father[1001000], ac[4][2] ={0, 1, 0, -1, -1, 0, 1, 0};
 8 struct node 
 9 {
10     int a, b;
11     int w;
12 } map[2001000];
13 bool cmp(node a, node b)
14 {
15     return a.w < b.w;
16 }
17 void init(int n)
18 {
19     for(int  i = 1; i <= n; i++)
20         father[i] = i;    
21 } 
22 int find(int a)
23 {
24     int r, k, j;
25     r = a;
26     while(r != father[r])
27         r = father[r];
28     j = a;
29     while(j != r)
30     {
31         k = father[j];
32         father[j] = r;
33         j = k;
34     }
35     return r;
36 }
37 bool mercy(int a, int b)
38 {
39     int q = find(a);
40     int p = find(b);
41     if(q != p)
42     {
43         father[q] = p;
44         return true;
45     }
46     else 
47         return false;
48 } 
49 int main()
50 {
51      // freopen("input.txt","r",stdin);
52     int t, temp = 1;
53     scanf("%d", &t);
54     while(t--)
55     {
56         int n, m, p = 0; 
57         scanf("%d %d", &n, &m);
58         init(n*m);
59     //    for(int i = 1; i <= n; i++)    
60     //        for(int j = 1; j <= m; j++)
61     //            scanf("%d", &num[i][j]);
62         for(int i = 1; i <= n; i++)                    /***************/
63         {
64             for(int j = 1; j <= m; j++)
65             {
66                 scanf("%d", &num[i][j]);
67                 int a = (i-1)*m + j;
68                 if(j > 1)
69                 {
70                     map[p].a = a;
71                     map[p].b = a - 1;
72                     map[p++].w = abs(num[i][j] - num[i][j-1]);
73                 }
74                 if(i > 1)
75                 {
76                     map[p].a = a;
77                     map[p].b = a - m;
78                     map[p++].w = abs(num[i][j] - num[i-1][j]);
79                 }
80             }
81         }                                              /*********************/
82         int sum = 0; 
83         sort(map, map + p, cmp);
84         int tt = 0;
85         for(int i = 0; i < p; i++)
86         {
87             if(mercy(map[i].a, map[i].b))
88             {
89                 sum += map[i].w;
90                 tt++;
91             }
92             if(tt >= n*m-1)     //小优化； 
93             break; 
94         }
95         printf("Case #%d:\n", temp++);
96         printf("%d\n", sum);
97     }
98     return 0;
99 }