n,m=map(int,input().split())
array=[]
row,col=0,0
for i in range(n):
array.append(input())
for i in range(n):
if 'X' not in array[i]: #가로줄 검사
row+=1
for j in range(m): #세로줄 검사
if 'X' not in [array[i][j] for i in range(i)]:
col+=1
print(max(row,col))