#include <iterator>
#include <array>
#include <vector>
#include <functional>
#include <map>
#include <utility>
#include <cstdio>
template<typename T> struct ScanfSpecifier{};
#define DEF(T,V) template<> struct ScanfSpecifier<T>{static constexpr const char* value = V;};
DEF(char*,"%s")DEF(int,"%d")DEF(double,"%lf")DEF(float,"%f")DEF(char,"%c")DEF(const char*,"%s")DEF(unsigned long,"%lu")DEF(unsigned int, "%u")
#ifdef _MSC_VER
DEF(long long int,"%I64d")
#else
DEF(long long int,"%lld")
#endif
#undef DEF
template<typename T> int RD(T& arg){return std::scanf(ScanfSpecifier<T>::value, &arg);}
template<int S> int RD(char (&arg)[S]){return std::scanf("%s", arg);}
int RD(char* arg){return std::scanf("%s", arg);}
template<> int RD<char>(char& arg){return std::scanf(" %c", &arg);}
template<typename T, typename... Args> int RD(T& arg1, Args&... args) {return RD(arg1) + RD(args...);}
template<typename T> T RD(){T ret; RD(ret); return ret;}
template<typename It> void RDV(It begin, It end) { while(begin != end) RD(*begin++); }
template<typename C> void RDV(C& c) {RDV(std::begin(c), std::end(c));}
template<typename T> void WT(T arg) {std::printf(ScanfSpecifier<T>::value, arg); }
template<typename T, typename U> void WT(std::pair<T, U> arg) {std::printf("("); WT(arg.first); std::printf(", "); WT(arg.second); std::printf(")");}
template<typename... Args> void WT(Args... args) { int alc = 0; int dummy[] = {((alc++? std::printf(" "): 0), WT(args), 0)...}; }

template<typename... Args> void WTL(Args... args) { WT(args...); std::printf("\n"); }
template<typename It> void WTV(It begin, It end) { int alc = 0; while(begin != end) (alc++? std::printf(" "): 0), WT(*begin++); }
template<typename C> void WTV(const C& c) {WTV(std::begin(c), std::end(c));}
template<typename It> void WTVL(It begin, It end) { WTV(begin, end); std::printf("\n"); }
template<typename C> void WTVL(const C& c) {WTVL(std::begin(c), std::end(c));}




template<typename T>
struct Mapper
{
    int operator[](const T& v) { int& ret = table[v]; if(!ret) rtable[ret = table.size()] = v; return ret - 1; }
    template<typename... Args> int operator()(Args... args) { return (*this)[T(args...)]; }
    T rev(int idx){return rtable[idx + 1];}
    std::map<T, int> table;
    std::map<int, T> rtable;
};

template<typename T, int S>
struct ReferenceArray
{
    struct It {typename std::array<T*, S>::iterator it; T& operator*(){return **it;} void operator++(){it++;} bool operator!=(const It& other){return it != other.it;} };
    int size()const{return _ptr.size();}
    It begin()const{return {_ptr.begin()};}
    It end()const{return {_ptr.end()};}
    T& operator[](int idx)const{return *_ptr[idx];}
    mutable std::array<T*, S> _ptr;
};
template<typename T, typename... Args> 
ReferenceArray<T, sizeof...(Args) + 1> MAKEV(T& arg1, Args&... args) {return {&arg1, &args...};}

struct Range
{   
    struct It {   int num, step; int operator*(){return num;} void operator++(){num += step;} bool operator!=(const It& other){return num != other.num;} };
    Range(int ee):b(0),e(ee){}
    Range(int bb, int ee):b(bb), e(ee){}
    It begin(){return {b, (b < e? 1: -1)};}
    It end(){return {e, 0};}
    int b, e;
};

template<typename T> inline T& UMAX(T& x, T y){if(x < y)x = y; return x;}
template<typename T> inline T& UMIN(T& x, T y){if(y < x)x = y; return x;}
template<typename T, typename... Args> struct ArithmiticPromotion { typedef decltype(T() + typename ArithmiticPromotion<Args...>::type()) type; };
template<typename T, typename U> struct ArithmiticPromotion<T, U> { typedef decltype(T() + U()) type; };
template<typename T> struct ArithmiticPromotion<T, T> { typedef T type; };
template<typename T> struct ArithmiticPromotion<T> { typedef T type; };
template<typename T, typename U> typename ArithmiticPromotion<T, U>::type MAX(T a, U b) { return a < b? b: a; }
template<typename T, typename... Args> typename ArithmiticPromotion<T, Args...>::type MAX(T a, Args... args) { return MAX(a, MAX(args...)); }
template<typename T, typename U> typename ArithmiticPromotion<T, U>::type MIN(T a, U b) { return a < b? a: b; }
template<typename T, typename... Args> typename ArithmiticPromotion<T, Args...>::type MIN(T a, Args... args) { return MIN(a, MIN(args...)); }





//alias
//RD[L],RDV[L],WT[L],WTV[L] for i/o
using RG = Range;
//template
#include <vector>
#include <string>
#include <cstring>
#include <set>
#include <map>
#include <cstdlib>
#include <algorithm>
#include <functional>
using namespace std;

char S[200009];
char ans[200009];
int N, K;



int main()
{
    RD(N, K, S);
    for(int i: RG(N))
        S[i] -= 'A';
    S[N] = 1;

    int start = 0;
    for(int i: RG(N))
        if(S[N - 1 - i] != i % 2)
        {
            start = i;
            break;
        }

    int L = N - 1 - start + 1;

    int pos = 0;
    int head = S[0];
    int total = 0;
    for(int i = 0; pos < L && i < K; i++, total++)
    {
        if(head == 0)
            head ^= 1;
        else 
        {
            if((S[1 + pos] ^ ((pos & 1))) == head)
                head ^= 1;
            pos++;
        }    
    }


    for(int i = 1; i < L; i++)
    {
        int len = L - i;
        int to = i + min(pos, len);
        ans[i] = 'A' + (S[to] ^ ((to - i) & 1));
    }
    
    if(N & 1)
        ans[0] = 'A' + (head ^ ((K - total) & 1));
    else
        ans[0] = 'A' + head;

    for(int i = L; i < N; i++)
        ans[i] = S[i] + 'A';
    for(int i = L; i < N; i++)
        ans[i] = S[i] + 'A';
    WTL(ans);



}






Measured memory_bytes: 768