N=int(input())
S=str(input())
S=list(S)
S.reverse()
x=0
if S[0]=="#":
    x=1
    a=1
else:
    x=0
    a=0
for i in range(1,N):
    if S[i]=="#":
        x+=max(2,i-a-1)
        a=i
print(x)