//package myPackage;
import java.util.*;
public class MyClass {
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
int n=in.nextInt();
String s1=in.next();
char[]ch=s1.toCharArray();
StringBuilder sb=new StringBuilder();
for(int i=0;i<ch.length;i++) {
sb.append((char)((Character.getNumericValue(ch[i])-10+n)%26+'a'));
}
System.out.println(sb);
}
}
转化过程
Character.getNumericValue(ch[i])-10//小写字母在26个字母中的次序
Character.getNumericValue(ch[i])-10+n//向后移动n位
(Character.getNumericValue(ch[i])-10+n)%26//折叠回小写字母范围
(char)((Character.getNumericValue(ch[i])-10+n)%26+'a')//转化为char类型