#include<bits/stdc++.h>
using namespace std;
int main(){
	string s,ans = "",ans1 = "";
	getline(cin,s);
	for (int i = 0;i < s.size();i++){
		if (s[i] == ' '){
			if (ans1.size() > ans.size()) ans = ans1;
			ans1 = "";
		}else{
			ans1 = ans1 + s[i];
		}
	}
	cout << ans;
	return 0;
}

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