for _ in range(int(input())):
n, m = map(int, input().split())
l = [input() for i in range(n)]
D = [[0] * m for i in range(n)]
ans = 0
for i in range(n):
for j in range(m):
if i > 0:
D[i][j] = max(D[i][j], D[i - 1][j])
if j > 0:
D[i][j] = max(D[i][j], D[i][j - 1])
if l[i][j] == 'C':
D[i][j] += 1
ans = max(ans, max(D[i]))
print(ans)