N = int(input())
X = []
Y = []
U = []
V = []
for i in range(N):
    S = input().strip()
    for j in range(2*N):
        if j<N and S[j]=="#":
            U.append(j)
            V.append(i)
        elif j>=N and S[j]==".":
            X.append(j)
            Y.append(i)
ans = sum(X)-sum(U)
Y = sorted(Y)
V = sorted(V)
if len(Y)==0:
    print(0)
else:
    for i in range(N):
        ans += abs(Y[i]-V[i])
    print(ans)