#include <iostream>
using namespace std;
int main(){
    string s;   getline(cin, s);
    string res = "", word = "";
    for(int i = 0; i < s.size() - 1; i ++ ){
        if(s[i] != ' ')  word += s[i];
        else{
            if(res.size() < word.size())    res = word;
            word = "";
        }
    }
    if(res.size() < word.size())    res = word;
    cout << res << endl;
    return 0;
}