class Solution { public String solution(String s, int n) { String answer = ""; for(char c : s.toCharArray()){ if(c == ' '){ answer += " "; }else if(Character.isLowerCase(c)){ c = (char)('a'+ (c-'a'+n)%26); answer += c; }else if(Character.isUpperCase(c)){ c = (char)('A'+ (c-'A'+n)%26); answer += c; } } return answer; } }