#include<bits/stdc++.h>
using namespace std;
 
#define debug(x) cerr << #x << ": " << (x) << endl
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define dwn(i,a,b) for(int i=(a);i>=(b);i--)
#define pb push_back
#define all(x) (x).begin(), (x).end()
 
#define x first
#define y second
using pii = pair<int, int>;
using ll = long long;
 
inline void read(int &x){
    int s=0; x=1;
    char ch=getchar();
    while(ch<'0' || ch>'9') {if(ch=='-')x=-1;ch=getchar();}
    while(ch>='0' && ch<='9') s=(s<<3)+(s<<1)+ch-'0',ch=getchar();
    x*=s;
}

const int N=13*13*14+5;

int n, K;
string s;
bitset<N> f[41][41][401];

void print(int idx, int a, int b, int c){
	if(!idx) return;
	int pi, pa, pb, pc;
	char res, cur=s[idx];
	if(cur=='N'){
		pi=idx-1, pa=a-1, pb=b, pc=c;
	}
	else if(cur=='A'){
		pi=idx-1, pa=a, pb=b-a, pc=c;
	}
	else if(cur=='C'){
		pi=idx-1, pa=a, pb=b, pc=c-b;
	}
	else if(isalpha(cur)){
		pi=idx-1, pa=a, pb=b, pc=c;
	}
	else{
		if(a>=1 && f[idx-1][a-1][b][c]) pi=idx-1, pa=a-1, pb=b, pc=c, res='N';
		if(b>=a && f[idx-1][a][b-a][c]) pi=idx-1, pa=a, pb=b-a, pc=c, res='A';
		if(c>=b && f[idx-1][a][b][c-b]) pi=idx-1, pa=a, pb=b, pc=c-b, res='C';
		if(f[idx-1][a][b][c]) pi=idx-1, pa=a, pb=b, pc=c, res='T';
	}
	
	if(isalpha(cur)) res=cur;
	
	print(pi, pa, pb, pc);
	
	putchar(res);
}

signed main(){
	cin>>n>>K;
	cin>>s;
	s=" "+s;
	
	if(K>=N){
		puts("-1");
		return 0;
	}
	// debug(sizeof f);
	
	f[0][0][0][0]=1;
	rep(i, 1, n){
		char c=s[i];
		if(c=='N'){
			rep(a, 1, 40) rep(b, 0, 400) f[i][a][b]=f[i-1][a-1][b]; 
		}
		else if(c=='A'){
			rep(a, 0, 40) rep(b, a, 400) f[i][a][b]=f[i-1][a][b-a];
		}
		else if(c=='C'){
			rep(a, 0, 40) rep(b, 0, 400) f[i][a][b]=f[i-1][a][b]<<b;
		}
		else if(isalpha(c)){
			rep(a, 0, 40) rep(b, 0, 400) f[i][a][b]=f[i-1][a][b];
		}
		else{
			rep(a, 0, 40) rep(b, 0, 400) f[i][a][b]=f[i-1][a][b];
			rep(a, 1, 40) rep(b, 0, 400) f[i][a][b]|=f[i-1][a-1][b]; 
			rep(a, 0, 40) rep(b, a, 400) f[i][a][b]|=f[i-1][a][b-a];
			rep(a, 0, 40) rep(b, 0, 400) f[i][a][b]|=f[i-1][a][b]<<b;
			// debug(f[1][1][0][0]);
			// debug(f[2][1][1][0]);
		}
	}
	
	int A=-1, B;
	rep(a, 0, 40) rep(b, 0, 400) if(f[n][a][b][K]){
		A=a, B=b;
	}
	if(A==-1){
		puts("-1");
		return 0;
	}
	
	print(n, A, B, K);
	
	return 0;
}