/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author majk
 */

#ifndef MAJK_LIB
#define MAJK_LIB

#include <vector>
#include <stack>
#include <iostream>
#include <unordered_map>
#include <unordered_set>
#include <map>
#include <iomanip>
#include <set>
#include <functional>
#include <fstream>
#include <algorithm>
#include <cassert>
#include <cmath>
#include <string>
#include <sstream>
#include <queue>
#include <array>
#include <bitset>
using namespace std;

#define x first
#define y second
typedef std::pair<int,int> pii; typedef long long ll; typedef unsigned long long ull; typedef unsigned int ui; typedef pair<ui,ui> puu;

template <typename T, typename U> std::istream&operator>>(std::istream&i, pair<T,U>&p) {i >> p.x >> p.y; return i;}
template<typename T>std::istream&operator>>(std::istream&i,vector<T>&t) {for(auto&v:t){i>>v;}return i;}
template <typename T, typename U> std::ostream&operator<<(std::ostream&o, const pair<T,U>&p) {o << p.x << ' ' << p.y; return o;}
template<typename T>std::ostream&operator<<(std::ostream&o,const vector<T>&t) {if(t.empty())o<<'\n';for(size_t i=0;i<t.size();++i){o<<t[i]<<" \n"[i == t.size()-1];}return o;}
template<typename T> using minheap = priority_queue<T, vector<T>, greater<T>>;
template<typename T> using maxheap = priority_queue<T, vector<T>, less<T>>;
template <typename T> bool in(T a, T b, T c) { return a <= b && b < c; }
ui logceil(ll x) { return x?8*sizeof(ll)-__builtin_clzll(x):0; }

namespace std { template<typename T,typename U>struct hash<pair<T,U>>{hash<T>t;hash<U>u;size_t operator()(const pair<T,U>&p)const{return t(p.x)^(u(p.y)<<7);}}; }
template<typename T,typename F>T bsh(T l,T h,const F&f){T r=-1,m;while(l<=h){m=(l+h)/2;if(f(m)){l=m+1;r=m;}else{h=m-1;}}return r;}
template<typename F> double bshd(double l,double h,const F&f,double p=1e-9){ui r=3+(ui)log2((h-l)/p);while(r--){double m=(l+h)/2;if(f(m)){l=m;}else{h=m;}}return (l+h)/2;}
template<typename T,typename F>T bsl(T l,T h,const F&f){T r=-1,m;while(l<=h){m=(l+h)/2;if(f(m)){h=m-1;r=m;}else{l=m+1;}}return r;}
template<typename F> double bsld(double l,double h,const F&f,double p=1e-9){ui r=3+(ui)log2((h-l)/p);while(r--){double m=(l+h)/2;if(f(m)){h=m;}else{l=m;}}return (l+h)/2;}
template<typename T> T gcd(T a,T b) { if (a<b) swap(a,b); return b?gcd(b,a%b):a; }

template<typename T>class vector2:public vector<vector<T>>{public:vector2(){} vector2(size_t a,size_t b,T t=T()):vector<vector<T>>(a,vector<T>(b,t)){}};
template<typename T>class vector3:public vector<vector2<T>>{public:vector3(){} vector3(size_t a,size_t b,size_t c,T t=T()):vector<vector2<T>>(a,vector2<T>(b,c,t)){}};
template<typename T>class vector4:public vector<vector3<T>>{public:vector4(){} vector4(size_t a,size_t b,size_t c,size_t d,T t=T()):vector<vector3<T>>(a,vector3<T>(b,c,d,t)){}};
template<typename T>class vector5:public vector<vector4<T>>{public:vector5(){} vector5(size_t a,size_t b,size_t c,size_t d,size_t e,T t=T()):vector<vector4<T>>(a,vector4<T>(b,c,d,e,t)){}};


#endif
// #include "../l/mod.h"

class DHalfReflector {
public:
    void solve(istream& cin, ostream& cout) {
        int N, K; cin >> N >> K;
        string S; cin >> S;
//        if (N == 1) {
//            if (K % 2 == 0) cout << S << endl;
//            else cout << "AB"[S[0] == 'A'] << endl;
//            return;
//        }

        deque<int> W;
        for (int i = 0; i < N; ++i) {
            if (i > 0 && S[i-1] == S[i]) W.back()++;
            else W.push_back(1);
        }
        bool firstA = S[0] == 'A';
        int R = W.size();
        for (int i = 0; i < min(2*N + K%2, K); ++i) {

            if (firstA) {
                if (W.front() == 1) {
                    --R;
                    W.pop_front();
                    W.front()++;
                } else {
                    ++R;
                    W.front()--;
                    W.push_front(1);
                }
                firstA = false;
            } else {
                if (W.front() == 1) {
                    W.pop_front(); --R;
                } else {
                    W.front()--; firstA = true;
                }
                if (W.size()%2==firstA) W.back()++;
                else { W.push_back(1); ++R; }
            }
        }

        stringstream ss;
        while (!W.empty()) {
            ss << string(W.front(), "BA"[firstA]);
            W.pop_front();
            firstA = !firstA;
        }
        cout << ss.str() << '\n';

//        for (int i = 0; i < K; ++i) {
//            int j = 0; int left = 1;
//            while (in(0, j, N)) {
//                bool straight = S[j] == 'B';
//                S[j] = "BA"[straight];
//                if (straight) j += left;
//                else { j -= left; left = -left; }
//            }
//        }
//        cout << S << '\n';
    }
};


int main() {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
	DHalfReflector solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
	solver.solve(in, out);
    return 0;
}


Measured memory_bytes: 1940