Problem:
 Score : 400 points    Problem Statement There are N people standing in a queue from west to east.  Given is a string S of length N representing the directions of the people.
The i -th person from the west is facing west if the i -th character of S is L , and east if that character of S is R .  A person is happy if the person in front of him/her is facing the same direction.
If no person is standing in front of a person, however, he/she is not happy.  You can perform the following operation any number of times between 0 and K (inclusive):  Operation: Choose integers l and r such that 1 \leq l \leq r \leq N , and rotate by 180 degrees the part of the queue: the l -th, (l+1) -th, ... , r -th persons. That is, for each i = 0, 1, ..., r-l , the (l + i) -th person from the west will stand the (r - i) -th from the west after the operation, facing east if he/she is facing west now, and vice versa.  What is the maximum possible number of happy people you can have?      Constraints  N is an integer satisfying 1 \leq N \leq 10^5 .  K is an integer satisfying 1 \leq K \leq 10^5 .  |S| = N  Each character of S is L or R .         Input Input is given from Standard Input in the following format:  N  K  S       Output Print the maximum possible number of happy people after at most K operations.        Sample Input 1 6 1
LRLRRL      Sample Output 1 3  If we choose (l, r) = (2, 5) , we have LLLRLL , where the 2 -nd, 3 -rd, and 6 -th persons from the west are happy.       Sample Input 2 13 3
LRRLRLRRLRLLR      Sample Output 2 9       Sample Input 3 10 1
LLLLLRRRRR      Sample Output 3 9       Sample Input 4 9 2
RRRLRLRLL      Sample Output 4 7

Solution (Python):
def main(sample_file = ''):

    """ convenient functions
    
    
    
    
    
    """

    """convenient decorator
    
    
        
        
        
        
        
        
        
        
        
        
    """
    
    
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product 
    
    from math import factorial, ceil, floor, sqrt
    def factorize(n):
        """return the factors of the Arg and count of each factor
        
        Args:
            n (long): number to be resolved into factors
        
        Returns:
            list of tuples: factorize(220) returns [(2, 2), (5, 1), (11, 1)]
        """
        fct = []  
        b, e = 2, 0  
        while b * b <= n:
            while n % b == 0:
                n = n // b
                e = e + 1
            if e > 0:
                fct.append((b, e))
            b, e = b + 1, 0
        if n > 1:
            fct.append((n, 1))
        return fct
    def combinations_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        
        if n < 0 or r < 0:
            raise Exception('combinations_count(n, r) not defined when n or r is negative')
        if n - r < r: r = n - r
        if r < 0: return 0
        if r == 0: return 1
        if r == 1: return n
        numerator = [n - r + k + 1 for k in range(r)]
        denominator = [k + 1 for k in range(r)]
        for p in range(2,r+1):
            pivot = denominator[p - 1]
            if pivot > 1:
                offset = (n - r) % p
                for k in range(p-1,r,p):
                    numerator[k - offset] /= pivot
                    denominator[k] /= pivot
        result = 1
        for k in range(r):
            if numerator[k] > 1:
                result *= int(numerator[k])
        return result
    def combinations_with_replacement_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items allowing individual elements to be repeated more than once.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        if n < 0 or r < 0:
            raise Exception('combinations_with_replacement_count(n, r) not defined when n or r is negative')
        elif n == 0:
            return 1
        else:
            return combinations_count(n + r - 1, r)
    from bisect import bisect_left, bisect_right
    from collections import deque, Counter, defaultdict 
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest 
    from copy import deepcopy, copy 
    import operator
    from operator import itemgetter 
    
    
    from functools import reduce, lru_cache
    def chmin(x, y):
        """change minimum
        if x > y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current minimum value
            y (long): potential minimum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x > y:
            x = y
            return (x, True)
        else:
            return (x, False)
    def chmax(x, y):
        """change maximum
        if x < y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current maximum value
            y (long): potential maximum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x < y:
            x = y
            return (x, True)
        else:
            return (x, False)

    from fractions import gcd 
    def gcds(numbers):
        return reduce(gcd, numbers)
    def lcm(x, y):
        return (x * y) // gcd(x, y)
    def lcms(numbers):
        return reduce(lcm, numbers, 1)
    def make_divisors(n, reversed=False):
        """create list of divisors
        
        Args:
            number (int): number from which list of divisors is created
            reversed (bool, optional): ascending order if False. Defaults to False.
        
        Returns:
            list: list of divisors
        """
        divisors = set()
        for i in range(1, int(n**0.5)+1):
            if n % i == 0:
                divisors.add(i)
                divisors.add(n//i)
        return sorted(list(divisors),reverse=reversed)
    
    
    
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    modpow = lambda a, n, p = MOD: pow(a, n, p) 
    def modinv(a, p = MOD):
        
        
        return modpow(a, p-2, p)
    def modinv_list(n, p = MOD):
        if n <= 1:
            return [0,1][:n+1]
        else:
            inv_t = [0,1]
            for i in range(2, n+1):
                inv_t += [inv_t[p % i] * (p - int(p / i)) % p]
            return inv_t
    def modfactorial_list(n, p = MOD):
        if n == 0:
            return [1]
        else:
            l = [0] * (n+1)
            tmp = 1
            for i in range(1, n+1):
                tmp = tmp * i % p
                l[i] = tmp
            return l
    def modcomb(n, k, fac_list = [], p = MOD):
        
        
        from math import factorial
        if n < 0 or k < 0 or n < k: return 0
        if n == 0 or k == 0: return 1
        if len(fac_list) <= n:
            a = factorial(n) % p
            b = factorial(k) % p
            c = factorial(n-k) % p
        else:
            a = fac_list[n]
            b = fac_list[k]
            c = fac_list[n-k]
        return (a * modpow(b, p-2, p) * modpow(c, p-2, p)) % p
    def modadd(a, b, p = MOD):
        return (a + b) % MOD
    def modsub(a, b, p = MOD):
        return (a - b) % p
    def modmul(a, b, p = MOD):
        return ((a % p) * (b % p)) % p
    def moddiv(a, b, p = MOD):
        return modmul(a, modpow(b, p-2, p))

    class UnionFindTree:
        """union find tree class
        TODO: fix this description...
        how to use (example):
        >>  uf = UnionFindTree(N) 
        >>  if uf.find_root(a) == uf.find_root(b):
        >>      do something
        >>  else:
        >>      do something
        >>      uf.unite(a, b)
        """
        def __init__(self, N):
            self.root = [-1] * (N+1)
            self.rank   = [0]  * (N+1)
            self.connected_num = [1] * (N+1)
    
        def find_root(self,x):
            root = self.root
            while root[x] != -1:
                x = root[x]
            return x
    
        def unite(self,x,y):
            root = self.root
            rank = self.rank
            connected_num = self.connected_num
            find_root = self.find_root
    
            rx = find_root(x)
            ry = find_root(y)
            if rx != ry:
                if rank[rx] < rank[ry]:
                    root[rx] = ry
                    rx,ry = ry,rx
                else:
                    if rank[rx] == rank[ry]:
                        rank[rx] += 1
                    root[ry] = rx       
                connected_num[rx] += connected_num[ry]

    
    
    
    
    

    def BellmanFord(N, M, ABC, vertex_start, vertex_end, value_if_inf = -1, find_shortest = False):
        """to calculate furthest or shortest length between vertex_start and vertex_end using BellmanFord algorithm
        
        Args:
            N (int): number of vertices
            M (int): number of edges
            ABC (list): [(ai, bi, ci) for _ in range(N)] where i-th edge is directed from vertex ai to vertex bi and the length is ci 
            vertex_start (int): start vertex. usually use 0.
            vertex_end (int): end vertex. usually use N-1.
            value_if_inf (int or string as you like, optional): value you want when the furthest (or shortest) distance is infinite (or -infinite). Defaults to -1.
            find_shortest (bool, optional): choose False to find furthest path. Defaults to False.
        
        Returns:
            int or string: normally int (but can be str if you set value_if_inf to str)
            
        Example:
                N, M, P = R()
                ABC = [R() for _ in range(M)]
                ABC = [(a-1, b-1, c-P) for a, b, c in ABC]
                print(BellmanFord(N, M, ABC, 0, N-1, value_if_inf = 'inf'))

        """

        def make_reachable_list(N, M, ABC, vertex_start, vertex_end):
            reachable_to_direct = defaultdict(list)
            reachable_from_direct = defaultdict(list)
            reachable_from_start = [False] * N
            reachable_to_end = [False] * N
            reachable_from_start[vertex_start] = True
            reachable_to_end[vertex_end] = True
            reachable_from_both_sides = [False] * N
            dfs_from_start = []
            dfs_to_end = []
            for a, b, c in ABC:
                reachable_to_direct[a].append(b)
                reachable_from_direct[b].append(a)
                if a == vertex_start:
                    dfs_from_start.append(b)
                    reachable_from_start[b] = True
                if b == vertex_end:
                    dfs_to_end.append(a)
                    reachable_to_end[a] = True
            while dfs_from_start:
                v = dfs_from_start.pop()
                for i in reachable_to_direct[v]:
                    if not reachable_from_start[i]:
                        reachable_from_start[i] = True
                        dfs_from_start.append(i)
            while dfs_to_end:
                v = dfs_to_end.pop()
                for i in reachable_from_direct[v]:
                    if not reachable_to_end[i]:
                        reachable_to_end[i] = True
                        dfs_to_end.append(i)
            for i in range(N):
                reachable_from_both_sides[i] = reachable_from_start[i] and reachable_to_end[i]
            return reachable_from_both_sides
        
        reachable_from_both_sides = make_reachable_list(N, M, ABC, vertex_start, vertex_end)
        
        if find_shortest:
            dist = [INF for i in range(N)]
        else:
            dist = [-INF for i in range(N)]
        
        dist[vertex_start] = 0
        for i in range(N):
            updated = False
            for a, b, c in ABC:
                if not reachable_from_both_sides[a]:
                    continue
                elif find_shortest:
                    update_condition = dist[a] + c < dist[b]
                else:
                    update_condition = dist[a] + c > dist[b]
                if dist[a] != INF and update_condition:
                    dist[b] = dist[a] + c
                    updated = True
                    if i == N-1:
                        return value_if_inf
            if not updated:
                break
        return dist[vertex_end]

    """ initialize variables and set inputs
    
        
        
    
        
        
        
        
        
        
        
    
        
        
        
        
    
        
        
    """

    
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    R = lambda: list(map(int, r().split()))
    Rmap = lambda: map(int, r().split())
    Rfloat = lambda: list(map(float, r().split()))
    Rtuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    
    
    
    
    
    
    
    """

    
    if sample_file:
        sys.stdin = open(sample_file)
        
    
    

    N, K = R()
    S = r()
    lr = 0
    rl = 0
    pr = S[0]
    ans = 0
    for s in S[1:]:
        if pr == 'L' and s == 'R':
            lr += 1
        elif pr == 'R' and s == 'L':
            rl += 1
        elif pr == s:
            ans += 1
        pr = s
    mn = min(lr, rl)
    ans += min(K, mn) * 2
    if K - mn > 0:
        ans += min(K-mn, max(lr, rl)-mn)
    print(ans)

    
    
    

    """memo: how to use defaultdict of list
    
    Dic = defaultdict(list)
    
    Dic[x].append(y)
    
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    
    >>> a = 5
    >>> bin_str_a = format(a, '
    >>> print(bin_str_a)
    0b0101 
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Solution (Python):
n,k = map(int,input().split())
s = input()
h = 0
if s[0] == 'R':
    if s[1] == 'R':
        h = h+1

if s[n-1] == 'L':
    if s[n-2] == 'L':
        h = h+1
        
for i in range(1,n-1):
    if s[i] == 'R':
        if s[i+1] == 'R':
            h = h+1
    else:
        if s[i-1] == 'L':
            h = h+1

if (h + 2*k) >= n:
    print(n-1)
else:
    print(h + 2*k)

Solution (Python):

import sys
from itertools import groupby


def solve(N: int, K: int, S: str):
    L = [len(list(g)) for k, g in groupby(S)]
    score = N - len(L)
    plus = min(2*K, len(L)-1)
    score += plus
    print(score)
    return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  
    K = int(next(tokens))  
    S = next(tokens)  
    solve(N, K, S)

if __name__ == '__main__':
    main()

Solution (Python):
n,k=map(int,input().split())
statas=input()
subs=[]
count=1
buf=statas[0]
for string in statas[1:]:
    if buf==string:
        count+=1
    else:
        subs.append(count)
        count=1
        buf=string
if (len(subs)+1)//2 <= k:
    print(n-1)
else:
    print(n-1-len(subs)+2*k)

Solution (Python):
n,k = map(int,input().split())	
s=list(input())
a=0
b=0
c=0
for i in range(n-1):
    if(s[i]=="L" and s[i+1]=="R"):
        a+=1
    elif(s[i]=="R" and s[i+1]=="L"):
        b+=1
    else:
        c+=1
ans=c+min(a,b,k)*2
if( min(a,b,k)<k ):
    q=min(a,b,k)
    a-=q
    b-=q
    if((a==0 and b==1) or (a==1 and b==0)):
        ans+=1
    
print(ans)

Solution (Python):

import sys


def solve(N: int, K: int, S: str):
    count = 0
    for i in range(N-1):
        if S[i] == S[i+1]:
            count += 1
    print(min(count + K * 2, N-1))
    return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  
    K = int(next(tokens))  
    S = next(tokens)  
    solve(N, K, S)

if __name__ == '__main__':
    main()

Solution (Python):
def resolve():
    n,k=map(int,input().split())
    S=input()
    lr=0
    rl=0
    score=0
    for i in range(n-1):
        score+=(S[i]==S[i+1])
        lr+=(S[i]=="L" and S[i+1]=="R")
        rl+=(S[i]=="R" and S[i+1]=="L")
    print(score+min(k,lr)+min(k,rl))
resolve()

Solution (Python):
import sys
def input():
    return sys.stdin.readline()[:-1]
inf=float("inf")
n,k=map(int,input().split())
s=input()
cnt=[]
tmp=[1,s[0]]
for i in range(1,n):
    if s[i]==tmp[1]:
        tmp[0]+=1
    else:
        cnt.append(tmp[0])
        tmp=[1,s[i]]
cnt.append(tmp[0])

ans=sum(cnt[:1+2*k])
left=0
right=0
for i in range(len(cnt)-1-2*k):
    right+=cnt[1+2*k+i]-1

tmp=left+ans+right
for i in range(len(cnt)-1-2*k):
    tmp1=left+ans+right
    left+=cnt[i]-1
    ans+=cnt[i+1+2*k]-cnt[i]
    right-=cnt[i+1+2*k]+1
    if tmp1<left+ans+right:
        tmp=left+ans+right
print(tmp-1)

Solution (Python):

import sys


def solve(N: int, K: int, S: str):
    count = 0
    for i in range(N-1):
        if S[i] == S[i+1]:
            count += 1
    result = min(count + K * 2, N-1)
    print(result)
    return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  
    K = int(next(tokens))  
    S = next(tokens)  
    solve(N, K, S)

if __name__ == '__main__':
    main()

Solution (Python):
import sys

sys.setrecursionlimit(10**7)
INF = 10 ** 18
MOD = 10 ** 9 + 7
def LI(): return list(map(int, sys.stdin.readline().split()))
def II(): return int(sys.stdin.readline())
def LS(): return list(map(list, sys.stdin.readline().split()))
def S(): return list(sys.stdin.readline())[:-1]

def main():
    n, k = LI()
    s = S()
    conb = []
    for i in range(n-1):
        conb.append(s[i] == s[i+1])
    print(min(sum(conb) + k * 2, n-1))




if __name__ == '__main__':
    main()

Solution (Python):
N,K = map(int, input().split())
S = input()
Ans = 0
max = N - 1

for i in range(N-1):
  if S[i] == S[i+1]:
    Ans = Ans + 1

Ans = Ans + 2 * K
if Ans >= max:
  Ans = max

print(Ans)

Solution (Python):
N, K = [ int(n) for n in input().split() ]
S = input()

happy = 0
LR = 0
RL = 0
for i in range(N-1):
    s = S[i:i+2]
    if s == "LR":
        LR += 1
    elif s == "RL":
        RL += 1
    else:
        happy += 1

m = min(LR,RL)
M = max(LR,RL)
if M <= K:
    print(N-1)
elif m >= K:
    print(happy + 2*K)
else:
    print(N-2)

Solution (Python):
n, k = map(int, input().split())
s = list(input())
sn = []
cur = None
for c in s:
    if cur is not None:
        if c == cur:
            sn[-1] += 1
        else:
            sn.append(1)
    else:
        sn = [1]
    cur = c

while len(sn) >= 3:
    if k == 0:
        break
    a, b, c = sn.pop(), sn.pop(), sn.pop()
    sn.append(a+b+c)
    k -= 1
if k > 0:
    if len(sn) == 3:
        sn = [sn[0] + sn[1] + sn[2]]
    elif len(sn) == 2:
        sn = [sn[0] + sn[1]]

score = sum([s - 1 for s in sn])
print(score)

Solution (Python):
n, k = map(int, input().split())
prev = ''
cnt = 0
for c in input():
    if c != prev: cnt += 1
    prev = c
cnt = max(1, cnt - 2 * k)
print(n - cnt)

Solution (Python):
import sys
input = sys.stdin.readline

def main():
    N,K = map(int,input().split())
    S = input()[:-1]

    score = 0
    for i in range(N-1):
        if S[i] == S[i+1]:
            score += 1

    print(min(score+2*K,N-1))

if __name__ == "__main__":
    main()

Solution (Python):


n,k=map(int,input().split())
S=list(input())
tmp=0
cnt=-1

for i in range(n):
    if tmp!=S[i]:
        cnt+=1
    tmp=S[i]

if k*2>=cnt:
    print(n-1)
else:
    print(n-1-cnt+k*2)

Solution (Python):
N,K=[int(x) for x in input().split()]
S=input()
bg=S[0]
t=0
A=[]
for i in range(N):
    if S[i]==bg:
        t+=1
    else:
        A.append(t)
        bg=S[i]
        t=1
A.append(t)
ans=N - max( (len(A)-2*K) , 1)
print(ans)

Solution (Python):
n, k = map(int, input().split())
S = input()

boundaries = list()
for i in range(n - 1):
    c1, c2 = S[i], S[i + 1]
    if c1 != c2:
        boundaries.append(i)

ans = n - 1 - len(boundaries)
if len(boundaries) % 2 == 0:
    ans += (2 * min(k, len(boundaries) // 2))

else:
    if len(boundaries) // 2 + 1 <= k:
        ans += len(boundaries)
    elif len(boundaries) // 2 <= k:
        ans += (len(boundaries) - 1)
    else:
        ans += (2 * k)

print(ans)

Solution (Python):
N, K = map(int,input().split())
S = input()
count = 0
for i in range(len(S)-1):
    if S[i]!= S[i+1]: count +=1
ans = min(N-1, N-1-count+2*K)
print(ans)

Solution (Python):
n,k = [int(i) for i in input().split()]
s = input()
diff = 0

before = s[0]
for i in range(1,n):
    if before!=s[i]:
        diff += 1
    before = s[i]

diff -= 2*k
diff = max(0,diff) + 1
print(n-diff)

Solution (Python):
N, K = map(int, input().split())
S = input()
ans = 0
for i in range(N-1):
    if S[i] == S[i+1]:
        ans+=1
print(min(ans+K*2, N-1))

Solution (Python):
n,k=map(int,input().split())
S=list(input())
cnt=0
x=0

for i in range(1,n):
    if S[i]==S[i-1]:
        cnt+=1
    else:
        x+=cnt
        cnt=0
x+=cnt
print(min(x+2*k,n-1))

Solution (Python):
n, k =map(int,input().split())
s = input()
islands=1
for i in range(1, len(s)):
	if s[i] != s[i-1]:
		islands+=1
print(n - max(1,islands-2*k))

Solution (Python):
N, K = map(int, input().split())
S = input()
happy = 0
LR = 0
RL = 0
for i in range(N-1):
    if S[i] == S[i+1]:
        happy += 1
    elif S[i] == 'L':
        LR += 1
    else:
        RL += 1
turn = min(K, LR, RL)
happy += turn * 2
K -= turn
LR -= turn
RL -= turn
LRturn = min(K, LR)
happy += LRturn
K -= LRturn
LR -= LRturn
RLturn = min(K, RL)
happy += RLturn
K -= RLturn
RL -= RLturn
print(happy)

Solution (Python):
n, k = map(int, input().split())
s = input()

mae = s[0]
cnt = 0
happy = 0

if mae == "R":
    if n>=2:
        if s[1]=="R":
            happy += 1

for i in range(1,n):
    now = s[i]

    if now=="L":
        if mae=="L":
            happy += 1
    if now=="R":
        if i<n-1:
            if s[i+1]=="R":
                happy+=1


    if now != mae:
        cnt += 1

    mae = now

n_set = cnt//2
n_amari = cnt%2

if k <= n_set:
    happy += k*2
else:
    happy += n_set*2+n_amari

print(happy)

Solution (Python):
import sys
sys.setrecursionlimit(10**7)
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x) - 1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def II(): return int(sys.stdin.readline())
def SI(): return sys.stdin.readline().strip()
INF = 10 ** 18
MOD = 10 ** 9 + 7

debug = True
debug = False

def dprint(*objects):
    if debug == True:
        print(*objects)


def solve():
    N, K = LI()
    S = SI()


    point = 0
    for i in range(N):
        if i != 0:
            if S[i] == S[i-1]:
                point += 1

    rest_len = N-point
    
    
    
    
    
    print(min(point + 2*K, N-1))

solve()

Solution (Python):
N, K = map(int, input().split())
S = input()

c = 0
for i in range(N-1):
    if S[i] != S[i+1]:
        c += 1

if K*2 <= c:
    ans = N-1-c+K*2
else:
    ans = N-1
print(ans)

Solution (Python):
n, k = map(int, input().split())
s = input()
if n == 1:
    print(0)
else:
    happy = 0
    if s[0] == "R" and s[1] == "R":
        happy += 1
    if s[n - 1] == "L" and s[n - 2] == "L":
        happy += 1
    for i in range(1, n - 1):
        if s[i] == "L":
            if s[i - 1] == "L":
                happy += 1
        else:
            if s[i + 1] == "R":
                happy += 1
    lr = 0
    rl = 0
    for i in range(n - 1):
        if s[i] == "L" and s[i + 1] == "R":
            lr += 1
        elif s[i] == "R" and s[i + 1] == "L":
            rl += 1
    for i in range(k):
        if min(lr, rl) >= 1:
            happy += 2
            lr -= 1
            rl -= 1
        elif max(lr, rl) >= 1:
            happy += 1
            lr = max(lr - 1, 0)
            rl = max(rl - 1, 0)
    print(happy)

Solution (Python):
n, k = map(int, input().split())
s = input()

ans = 0
count = 1
for i in range(n-1):
    if s[i] == s[i+1]:
        ans += 1
    else:
        count += 1

for i in range(k):
    if count >= 3:
        count -= 2
        ans += 2
    elif count == 2:
        count -= 1
        ans += 1
    elif count == 1:
        break

print(ans)

Solution (Python):
n, k  = map(int, input().split())
s = list(input())

left = 0
right = n-1
count = 0
border = 0
tag = s[0]
if s[right] != tag:
    while s[right] != tag:
        right-=1
    border +=1
while True:
    while s[left] == tag and left < right:
        left+=1
    while s[right] == tag and left <= right:
        right -= 1
    if left == right:
        border += 2
        break
    if right < left:
        break
    border += 2
    if tag == 'L':
        tag = 'R'
    else:
        tag = 'L'

border = max(0, border - k * 2)
print(n - border -1)

Solution (Python):
(N,M) = (int(i) for i in input().split(" "))
S = input()
T = [S[0]]
for i in range(1,len(S)):
	if T[-1][-1] != S[i]:
		T.append(S[i])
	else:
		T[-1]+=S[i]
mp = [len(t) for t in T]
ans = len(S) - len(mp) + M*2
print(min(ans,len(S)-1))

Solution (Python):
n,k=map(int,input().split())
s=input()
s="x"+s+"x"
lr,rl=0,0
ans=0
for i in range(1,n+1):
  if s[i]=="L":
    if s[i-1]=="L":
      ans+=1
    if s[i+1]=="R":
      lr+=1
  else:
    if s[i+1]=="R":
      ans+=1
    elif s[i+1]=="L":
      rl+=1
if k<=min(lr,rl):
  ans+=2*k
else:
  ans+=2*min(lr,rl)
  k-=min(lr,rl)
  if k>=abs(lr-rl):
    ans+=abs(lr-rl)
  else:
    ans+=k
print(ans)

Solution (Python):
N, K = map(int, input().split())
S = 'R' + input() + 'L'
UH = [0] * (N + 1)
d = 'R'
for i, s in enumerate(S):
  if s == 'R':
    if S[i + 1] == 'L':
      UH[i] += 1
  else:
    if S[i - 1] == 'R':
      UH[i - 1] += 1
UH[0] = min(UH[0], 1)
UH[N] = min(UH[N], 1)
UH.sort(reverse=True)
for i in range(min(K, N + 1)):
  UH[i] = 0
if sum(UH) == 0:
  UH[0] = 1
print(N - sum(UH))

Solution (Python):

N,K = map(int,input().split())
S = list(input())

ans = 0
if S[0] == 'R':
    flagr = True
else:
    flagr = False

for i in range(1,N):
    if flagr:
        if S[i] == 'R':
            ans += 1
        else:
            flagr = False
    else:
        if S[i] == 'L':
            ans += 1
        else:
            flagr = True
            
ans = min(ans+2*K,N-1)
print(ans)

Solution (Python):
N, K = map(int, input().split())
S = input()

dup = 0
for i in range(1,N):
    if S[i] == S[i-1]:
        dup += 1
print(min(N-1, dup + K*2))

Solution (Python):
N,K = map(int, input().split())
S = list(input())
numL = S.count("L")
numR = S.count("R")

score = 0
turning = 0
for i in range(1, N):
	if S[i-1] == S[i]:
		score += 1
	else:
		turning += 1

if K >= (turning + 2) // 2:
	print(N-1)
else:
	print(score + 2*K)

Solution (Python):
n,k=map(int,input().split())
s=input()
g=0
for i in range(n):
    if i!=0:
        if s[i-1]==s[i] and s[i]=="L":
            g+=1
    if i!=n-1:
        if s[i+1]==s[i] and s[i]=="R":
            g+=1
print(min(n-1,g+2*k))

Solution (Python):

n,k = map(int, input().split( ))

s = input()





ans = n-1
tmp = 0
for i in range(n-1):
    if s[i] != s[i+1]:
        ans -= 1
        
ans += 2*k
print(min(ans,n-1))

Solution (Python):
import sys
sys.setrecursionlimit(10**7)
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x) - 1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def II(): return int(sys.stdin.readline())
def SI(): return sys.stdin.readline().strip()
def LILI(n): return [LI() for _ in range(n)]
INF = 10 ** 18
MOD = 10 ** 9 + 7

def main(): 
    N, K = LI()
    S = SI()

    wakareme = []
    current_koufuku = 0
    for i in range(N-1):
        if S[i] != S[i+1]:
            wakareme.append(i)
        else:
            current_koufuku += 1

    if 2*K < len(wakareme):
        print(current_koufuku + 2 * K)  
        return
    else:
        print(N-1)  
        return


main()

Solution (Python):
N,K= list(map(int, input().split()))
S=input()
before='A'
ans=0
for i in S:
    if i==before:
        ans+=1
    before=i
ans+=2*K
ans=min(ans,N-1)
print(ans)

Solution (Python):
n,k=map(int,input().split())
s=input()
a=[]
for i in range(n):
    if(s[i]=="L"):
        a.append(-1)
    else:
        a.append(1)
gen=0
for i in range(n):
    num=i+a[i]
    if(num>=0 and num <=n-1):
        if(a[i]*a[num]==1):
            gen+=1

ans=gen+k*2
if(ans>=n):
    ans=n-1
print(ans)

Solution (Python):
n,k = map(int,input().split())
s = input()
unhappy = s.count('RL')+s.count('LR')
happy = n-unhappy-1
happy = min(n-1,happy+2*k)
print(happy)

Solution (Python):
import collections as c
ip = lambda : map(int, input().split())

N,K = ip()
S = input()
l = []

c = 1
for i in range(1,N):
    if S[i] == S[i-1]:
        c+=1
    else:
        l.append(c)
        c=1
l.append(c)

ans = 0
K *= 2
ans += l[0]-1
for i in l[1:]:
    if K>0:
        K-=1
        ans+=i
    else:
        ans+=i-1
print(ans)

Solution (Python):
N,K=map(int,input().split())

S=list(input())


from itertools import groupby



gs=[len(list(group)) for key,group in groupby(S)]
now_ans = N-len(gs)
add_ans = now_ans + 2*K

ans=min(add_ans,N-1)




print(str(ans))

Solution (Python):

import sys


def solve(N: int, K: int, S: str):
    counter = 0
    for i, s in enumerate(S):
        if i > 0:
            if s == 'L' and S[i-1] == 'L':
                counter += 1
        if i < N-1:
            if s == 'R' and S[i+1] == 'R':
                counter += 1
    n = N - counter
    print(N - max(1, n - 2 * K))
    return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    N = int(next(tokens))  
    K = int(next(tokens))  
    S = next(tokens)  
    solve(N, K, S)

if __name__ == '__main__':
    main()

Solution (Python):
import sys; from collections import deque ; readline = sys.stdin.readline

N, K = map(int, readline().split())
S = readline().rstrip()

nhappy = 0
nseg = 0

state = None
for c in S:
    if c == state:
        nhappy += 1
    else:
        nseg += 1
        state = c

k = K
while k > 0:
    k -= 1
    if nseg >= 3:
        nseg -= 2
        nhappy += 2
    elif nseg == 2:
        nseg -= 1
        nhappy += 1
    else:
        break

print(nhappy)

Solution (Python):
N,K=map(int, input().split())
S=input()
a=0
for i in range(N-1):
    if S[i]==S[i+1]:
        a+=1
print(min((a+2*K),N-1))

Solution (Python):
n,k=map(int,input().split())
s=input()
first=0
for i in range(n):
  if s[i]=='L':
    if i!=n-1: 
      if s[i+1]=='L':
        first+=1
  else:
    if i!=0:
      if s[i-1]=='R':
        first+=1
ans=min(n-1,first+2*k)
print(ans)

Solution (Python):
N,K = map(int,input().split())
S = input()
ans=0
for i in range(N-1):
    if S[i]==S[i+1]:
        ans += 1
print(min(N-1,ans+2*K))

Solution (Python):
N, K = map(int, input().split())
S = input()

p = 0
ans = 0
i = 0
m = 0
while i < N:
    l = 1
    while i + l < N and S[i] == S[i + l]:
        l += 1
    ans += l - 1
    if p >= 2 and m < K:
        ans += 2
        p -= 2
        m += 1
    p += 1
    i += l
if m < K and p >= 2:
    ans += 1
print(ans)