Buggy python submission (verdict: Time Limit Exceeded):
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            for x in range(N-i):
                if C[chk-x] == 'R':
                    chk = chk - x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1
                if chk <= i + 1:
                    break

    print(cnt)

main_chk()


Fixed submission:
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            p = chk
            chk = i
            for x in range(N-i):
                if C[p-x] == 'R':
                    chk = p - x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1
                if chk <= i + 1:
                    break

    print(cnt)

main_chk()

Buggy python submission (verdict: Time Limit Exceeded):
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            for x in range(N-i):
                if C[chk-x] == 'R':
                    chk = chk - x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1

    print(cnt)

main_chk()


Fixed submission:
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            p = chk
            chk = i
            for x in range(N-i):
                if C[p-x] == 'R':
                    chk = p - x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1
                if chk <= i + 1:
                    break

    print(cnt)

main_chk()

Buggy python submission (verdict: Time Limit Exceeded):
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            for x in range(N):
                if C[chk-x] == 'R':
                    chk = chk - x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1

    print(cnt)

main_chk()

Fixed submission:
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            p = chk
            chk = i
            for x in range(N-i):
                if C[p-x] == 'R':
                    chk = p - x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1
                if chk <= i + 1:
                    break

    print(cnt)

main_chk()

Buggy python submission (verdict: Time Limit Exceeded):
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            for x in reversed(range(0,chk+1)):
                if C[x] == 'R':
                    chk = x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1

    print(cnt)

main_chk()


Fixed submission:
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            p = chk
            chk = i
            for x in range(N-i):
                if C[p-x] == 'R':
                    chk = p - x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1
                if chk <= i + 1:
                    break

    print(cnt)

main_chk()

Buggy python submission (verdict: Time Limit Exceeded):
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

N=int(input())
C=input()

chk = N - 1
cnt = 0

for i in range(N):
    if C[i] == 'W':
        for x in reversed(range(0,chk+1)):
            if C[x] == 'R':
                chk = x
                break
        if chk <= i:
            break
        else:
            cnt = cnt + 1
            chk = chk - 1

print(cnt)


Fixed submission:
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re

def main_chk():
    N=int(input())
    C=input()

    chk = N - 1
    cnt = 0

    for i in range(N):
        if C[i] == 'W':
            p = chk
            chk = i
            for x in range(N-i):
                if C[p-x] == 'R':
                    chk = p - x
                    break
            if chk <= i:
                break
            else:
                cnt = cnt + 1
                chk = chk - 1
                if chk <= i + 1:
                    break

    print(cnt)

main_chk()