Buggy python submission (verdict: Runtime Error):
n = int(input())
s = input()
a = []
#  .##..#.##.
w = s.count(".")
b = s.count("#")
m = min(w,b)

bb=0

for i in range(n):
    if s[i]=='.':
        w-=1
    if s[i]=='#':
        bb += 1
        a.append(bb+w)
n=min(a)
print(min(m,n))


Fixed submission:
n = int(input())
s = input()

a = []
#  .##..#.##.
w = s.count(".")
b = s.count("#")
m = min(w,b)

bb=0

for i in range(n):
    if s[i]=='.':
        w-=1
        a.append(bb+w)
    if s[i]=='#':
        bb += 1
        a.append(bb+w)
if len(a)>0:
    I = min(a)
    print(min(m,I))
else:
    print(m)

Buggy python submission (verdict: Runtime Error):
n = int(input())
s = input()
#white
i=0
numw=0
while s[i]==".":
    numw+=1
    i+=1
    if i == n:
        break
#  ..##.#..
w = s.count(".")
answ = w-numw

#black
j=-1
numb=0
while s[j]=="#":
    numb+=1
    j-=1
    if j*(-1) == n:
        break
b = s.count('#')
ansb=b-numb

#b&w
bw=0
k=numw
if k!=0:
    while s[k]=="#":
        k+=1
        bw+=1
        if k==n:
            break
wb=0
l=numb*(-1)-1
if l!=-1:
    while s[l]==".":
        l-=1
        wb+=1
        if l==n*(-1):
            break
ans3=bw+wb
print(min(ansb,answ,ans3))


Fixed submission:
n = int(input())
s = input()

a = []
#  .##..#.##.
w = s.count(".")
b = s.count("#")
m = min(w,b)

bb=0

for i in range(n):
    if s[i]=='.':
        w-=1
        a.append(bb+w)
    if s[i]=='#':
        bb += 1
        a.append(bb+w)
if len(a)>0:
    I = min(a)
    print(min(m,I))
else:
    print(m)

Buggy python submission (verdict: Runtime Error):
n = int(input())
s = input()
#white
i=0
numw=0
while s[i]==".":
    numw+=1
    i+=1
    if i == n:
        break
#  ..##.#..
w = s.count(".")
answ = (w-numw).copy()

#black
j=-1
numb=0
while s[j]=="#":
    numb+=1
    j-=1
    if j*(-1) == n:
        break
b = s.count('#')
ansb=(b-numb).copy()

#b&w
bw=0
k=numw.copy()
if k!=0:
    while s[k]=="#":
        k+=1
        bw+=1
        if k==n:
            break
wb=0
l=(numb*(-1)-1).copy()
if l!=-1:
    while s[l]==".":
        l-=1
        wb+=1
        if l==n*(-1):
            break
ans3=bw+wb
print(min(ansb,answ,ans3))


Fixed submission:
n = int(input())
s = input()

a = []
#  .##..#.##.
w = s.count(".")
b = s.count("#")
m = min(w,b)

bb=0

for i in range(n):
    if s[i]=='.':
        w-=1
        a.append(bb+w)
    if s[i]=='#':
        bb += 1
        a.append(bb+w)
if len(a)>0:
    I = min(a)
    print(min(m,I))
else:
    print(m)

Buggy python submission (verdict: Runtime Error):
n = int(input())
s = input()
#white
i=0
numw=0
while s[i]==".":
    numw+=1
    i+=1
    if i == n:
        break
#  ..##.#..
w = s.count(".")
answ = w-numw

#black
j=-1
numb=0
while s[j]=="#":
    numb+=1
    j-=1
    if j*(-1) == n:
        break
b = s.count('#')
ansb=b-numb

#b&w
bw=0
k=numw-1
if k!=0:
    while s[k]=="#":
        k+=1
        bw+=1
        if k==n:
            break
wb=0
l=numb*(-1)-1
if l!=-1:
    while s[l]==".":
        l-=1
        wb+=1
        if l==n*(-1):
            break
ans3=bw+wb

print(min(ansb,answ,ans3))


Fixed submission:
n = int(input())
s = input()

a = []
#  .##..#.##.
w = s.count(".")
b = s.count("#")
m = min(w,b)

bb=0

for i in range(n):
    if s[i]=='.':
        w-=1
        a.append(bb+w)
    if s[i]=='#':
        bb += 1
        a.append(bb+w)
if len(a)>0:
    I = min(a)
    print(min(m,I))
else:
    print(m)

Buggy python submission (verdict: Runtime Error):
n = int(input())
s = input()
#white
i=0
num=0
while s[i]==".":
    num+=1
    i+=1
    if i == n:
        break
#  ..##.#..
n = s.count(".")
answ = n-num

#black
j=-1
numb=0
while s[j]=="#":
    numb+=1
    j-=1
    if j*(-1) == n:
        break
m = s.count('#')
ansb=m-numb

if ansb<=answ:
    print(ansb)
else:
    print(answ)


Fixed submission:
n = int(input())
s = input()

a = []
#  .##..#.##.
w = s.count(".")
b = s.count("#")
m = min(w,b)

bb=0

for i in range(n):
    if s[i]=='.':
        w-=1
        a.append(bb+w)
    if s[i]=='#':
        bb += 1
        a.append(bb+w)
if len(a)>0:
    I = min(a)
    print(min(m,I))
else:
    print(m)

Buggy python submission (verdict: Runtime Error):
n = int(input())
s = input()
#white
i=0
num=0
while s[i]==".":
    num+=1
    i+=1
    if i == n:
        break
#  ..##.#..
n = s.count(".")
answ = n-num

#black
j=-1
numb
while s[j]=="#":
    numb+=1
    j-=1
    if j*(-1) == n:
        break
m = s.count('#')
ansb=m-numb

if ansb<=answ:
    print(ansb)
else:
    print(answ)


Fixed submission:
n = int(input())
s = input()

a = []
#  .##..#.##.
w = s.count(".")
b = s.count("#")
m = min(w,b)

bb=0

for i in range(n):
    if s[i]=='.':
        w-=1
        a.append(bb+w)
    if s[i]=='#':
        bb += 1
        a.append(bb+w)
if len(a)>0:
    I = min(a)
    print(min(m,I))
else:
    print(m)