#include <cstdio>
#include <iostream>
#include <sstream>
#include <cstring>

using namespace std;

int len;
int main()
{
    string s;
    getline(cin, s);

    string sub, ans;
    int flag = 0;               //统计当前单词的长度

    stringstream str(s);        //将字符串装进流内


    while(str>>sub)
    {
        len = (int)sub.length();
        if(!isalpha(sub[len-1]))    //主要为了消除最后一个标点符号"."
        {
            sub.erase(len-1);
        }

        if(sub.length() > flag)
        {
            ans = sub;
            flag = (int)sub.length();
        }
    }

    cout<<ans<<endl;

    return 0;
}