def getint(): return int(input())
def getints(): return list(map(int, input().split()))
def getintsm1(): return [int(x)-1 for x in input().split()]
T = int(input())

import numpy as np

def get(yx):
    return F[yx[0]][yx[1]] if all((0 <= yx) & (yx < [R,C])) else '#'

dirs = list(map(np.array, [[0,1],[0,-1],[1,0],[-1,0]]))

for caseno in range(T):
    R, C = getints()
    F = [input() for _ in range(R)]
    ifins = {}
    istarts = {}
    for y in range(R):
        for x in range(C):
            c = F[y][x]
            if c.isalpha():
                [istarts, ifins][c.isupper()][c] = np.array([y,x])
    
    result = []
    for fchar, f in ifins.items():
        success = {tuple(f)}
        pending = [f]
        while pending:
            x = pending.pop()
            for d in dirs:
                y = x
                while True:
                    y = y + d
                    c = get(y)
                    if c in '*#' or tuple(y) in success: break
                if c != '*':
                    y = y - d
                    while any(y != x):
                        success.add(tuple(y))
                        pending.append(y)
                        y = y - d
        for schar, s in istarts.items():
            if tuple(s) in success:
                result.append(schar + fchar)
    print(f"Case #{caseno + 1}:", *sorted(result or ['NONE']))