import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
 
public class Main {
	private static final char BAN1 = ' ';
	private static final char BAN2 = '.';
	private static final char BAN3 = ',';
 
	public static void main(String[] args) throws Exception{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		StringTokenizer st = new StringTokenizer(br.readLine());
 
		int k = Integer.parseInt(st.nextToken()) % 26;
		int s = Math.abs(Integer.parseInt(st.nextToken()));
		char[] words = br.readLine().toCharArray();
 
		for(int i = 0; i < s; i++) {
            // '.' ',' ' '의 경우 바로 버퍼에 담음
			if(words[i] == BAN1 || words[i] == BAN2 || words[i] == BAN3) {
				sb.append(words[i]);
				continue;
			}
 
			words[i] += k;    // 그 외 알파벳
 
            // (words[i] + k)가 ASCII 코드의 알파벳 범위를 벗어나는 경우
			if((words[i] > 'Z' && words[i] < 'a') || words[i] > 'z') words[i] %= 26;
 
			sb.append(words[i]);
		}
 
		System.out.println(sb.toString());
	}
}
 

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5 37
I love Red Black Tree, how about you.