#include <cstdio>

 #include <cstring>

 #include <utility>

 #include <set>

 #include <algorithm>

 #include <vector>

 using namespace std;

 const int MAXN =  + ;

 bool pic[MAXN][MAXN], record[MAXN][MAXN];

 const char *name = "WAKJSD";

 int f[MAXN][MAXN], dx[] = {, -, , }, dy[] = {, , -, };

 int cnt, H, W, T;

 vector<pair<int, int> > startp;

 void init_read() {

     char s[]; cnt = ; H += ; int NW =  * W + ;

     memset(pic, , sizeof(pic));

     memset(f, , sizeof(f));

     memset(record, , sizeof(record));

     startp.clear();

     for (int i = ; i < NW; i++) pic[][i] = pic[H - ][i] = ;

     for (int i = ; i < H; i++) pic[i][] = pic[i][NW - ] = ;

     for (int i = ; i < H - ; i++) {

         scanf("%s", s);

         for (int j = ; j < W; j++) {

             int num = s[j] > '' ? s[j] - 'a' +  : s[j] - '';

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

                 if (num >= ( << ( - k))) { pic[i][j *  + k + ] = ; num -= ( << ( - k));}

         }

     }

     W = NW;

 }

 void colorization(int x, int y, bool c) {

     f[x][y] = cnt;

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

         int nx = x + dx[i], ny = y + dy[i];

         if (nx >=  && ny >=  && nx < H && ny < W && pic[nx][ny] == c && !f[nx][ny])

             colorization(nx, ny, c);

     }

 }

 void floodfill() {

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

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

             if (!f[i][j]) {

                 cnt++; colorization(i, j, pic[i][j]);

                 if (pic[i][j]) startp.push_back(make_pair(i, j));

             }

 }

 void get_signiture(set<int> &signature, int x, int y) {

     record[x][y] = ;

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

         int nx = x + dx[i], ny = y + dy[i];

         if (nx >=  && ny >=  && nx < H && ny < W) {

             if (f[nx][ny] != f[x][y]) signature.insert(f[nx][ny]);

             else if(f[nx][ny] == f[x][y] && !record[nx][ny])

                 get_signiture(signature, nx, ny);

         }

     }

 }

 void recognize() {

     vector<char> ans;

     int n = startp.size();

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

         int x = startp[i].first, y = startp[i].second;

         set<int> signature;

         get_signiture(signature, x, y);

         ans.push_back(name[signature.size() - ]);

     }

     sort(ans.begin(), ans.end());

     printf("Case %d: ", ++T);

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

         printf("%c", ans[i]);

     printf("\n");

 }

 int main() {

     while (scanf("%d%d", &H, &W) ==  && H) {

         init_read();

         floodfill();

         recognize();

     }

     return ;

 }