UVA - 11636 - Hello World! (Java Solution)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuffer sb = new StringBuffer("");
        int arr[]=new int[16];
        for(int i=1,q=1;i<16;i++,q*=2){
            arr[i]=q;
        }
        int i=1;
        while(true) {
          int x=Integer.parseInt(br.readLine());
          if(x<0)
              break;
          int res=0;
          for(int j=0;j<arr.length;j++){
              if(arr[j]>=x){
                  res=j-1;
                  break;
              }
          }
          sb.append("Case ").append(i).append(": ").append(res).append("\n");
          i++;
        }
        System.out.print(sb);
    }
   
}