from __future__ import print_function
import sys

def eprint(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)


n=int(input())
S=list(input())

cnt_temp=0
stack=[]
cnt=0

# # eprint(n)
# # eprint(S)

# for i in range(n):
#     # eprint(i)


# flag=0
# flag2=0
start=0




if S[0] == '.':
    for i in range(n-1):
        if S[i]=='#' and S[i+1]=='.':
            for j in range(i+1,n):
                if S[j] =='.':
                    cnt_temp+=1
            break
else:
    for i in range(n):
        if S[i] == '.':
            cnt_temp+=1

        
# for _ in S:
#     eprint( _ , end="")
# eprint()
        
for i in range(n-1):
    if S[i]=='#' and S[i+1]=='#':
        stack.append(i)
    elif S[i]=='#' and S[i+1]=='.':
        
        S[i]='.'
        cnt+=1
        
        # for _ in S:
            # eprint(_,end="")
        # eprint()
        
        
        
        while stack!=[]:
            temp=stack.pop()
            S[temp]='.'
            cnt+=1
            # for _ in S:
                # eprint(_,end="")
            # eprint()

            
        
# eprint("cnt: ",end="")
# eprint(cnt)
# # eprint("cnt_temp2: ",end="")
# eprint(cnt_temp2)

print(min(cnt,cnt_temp))
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