import java.util.*; public class Solution { public String solve (int M, int N) { char symbol = '+'; if(M<0){ symbol = '-'; M = -M; } StringBuilder sb = new StringBuilder(); while(M>0){ int remainder = M%N; if(remainder>9){ char c = (char)('A'+(remainder-10)); sb.append(c); }else{ sb.append(remainder); } M = M/N; } if(symbol == '-'){ sb.append('-'); } return sb.reverse().toString(); } }