#include <iostream>
#include <sstream>
using namespace std;
int main()
{
string s;
int cnt = 0;
getline(cin, s);
s.pop_back(); //开始就把末尾的句号去掉,之后就不用特判了
stringstream ssin(s); //将字符串初始化为字符流,ssin用法同cin
string str, res;
while (ssin >> str)
if (str.size() > cnt)
cnt = str.size(), res = str;
cout << res << endl;
return 0;
}