R,I=range,input
N=int(I())
S=[I()for n in R(N)]
a=0
for i in R(N):
	a+=sum(S[i][j]=='.'for j in R(N))==1 and all(S[i][j]!='B'for j in R(N))
	a+=sum(S[j][i]=='.'for j in R(N))==1 and all(S[j][i]!='B'for j in R(N))
a+=sum(S[j][j]=='.'for j in R(N))==1 and all(S[j][j]!='B'for j in R(N))
a+=sum(S[N-1-j][j]=='.'for j in R(N))==1 and all(S[N-1-j][j]!='B'for j in R(N))
print(a)