import java.util.Scanner;

class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        char c = 'w';
        while(s.charAt(0) == c){
            s = s.substring(1);
        }

        String maxans = "";
        int maxgrass = 0;

        String ans = "";
        int grass = 0;

        StringBuilder sb = new StringBuilder();
        boolean inStr = true; // true - constructing string, false - counting w
        
        for(int i = 0; i < s.length(); i++){
            if(inStr && s.charAt(i) != c){
                sb.append(s.charAt(i));
            }else if(inStr && s.charAt(i) == c){
                ans = sb.toString();
                sb.setLength(0);
                grass = 1;
                inStr = false;
            }else if(!inStr && s.charAt(i) == c){
                grass++;
            }else if(!inStr && s.charAt(i) != c){
                inStr = true;
                sb.setLength(0);
                sb.append(s.charAt(i));
                if(grass > maxgrass){
                    maxans = ans;
                    maxgrass = grass;
                }else if(grass == maxgrass){
                    maxans = maxans + "\n" + ans;
                }
                grass = 0;
                ans = "";
            }
        }

        if(!inStr){
            if(grass > maxgrass){
                maxans = ans;
            }else if(grass == maxgrass){
                maxans = maxans + "\n" + ans;
            }
        }

        System.out.print(maxans);
    }
}