#include<iostream>
using namespace std;

int main(){
    string s1, s2;
    while(cin >> s1){
        if(s1.back() == '.')
            s1.pop_back();
        if(s1.size() > s2.size())
            s2 = s1;
    }
    cout << s2 << endl;
    return 0;
}

#include<iostream>
#include<sstream>
using namespace std;

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

    string s1;
    string s2;
    stringstream ssin(s);
    while(ssin >> s1){
        if(s1.back() == '.')
            s1.pop_back();
        if(s1.size() > s2.size())
            s2 = s1;
    }
    cout << s2 << endl;
    return 0;
}