process.stdin.resume();
process.stdin.setEncoding('utf8');
process.stdin.on('data', function(chunk) {
    main(chunk.trim());
});
function main(chunk){
    // your code goes here
    var words = [];
    var pool = "";
    var w_cnt = 0;
    var max_length = 0;
    for(var i in chunk){
        if(chunk[i]=='ｗ'){
            w_cnt++;
            if(pool!="")
                words.push({word:pool});
            pool = "";
        }else{
            if(w_cnt > 0 && words[words.length-1]){
                words[words.length-1].length = w_cnt;
            }
            max_length = Math.max(max_length,w_cnt);
            pool += chunk[i];
            w_cnt = 0;
        }
    }
    if(w_cnt > 0 && words[words.length-1])
        words[words.length-1].length = w_cnt;
    max_length = Math.max(max_length,w_cnt);
    pool += chunk[i];

    if(max_length==0){
        console.log("");
    }else{
        for(var i in words){
            if(words[i].length == max_length){
                console.log(words[i].word);
            }
        }
    }
}