#include <iostream>
#include <string>
using namespace std;
int main() {
string str;
getline(cin, str);
int longest=0;
int length=0;
string maxword, word;
char x;
for(int i=0; i<str.length(); i++)
{
x=str[i+1];
if(str[i]<=x)
{
length++;
word+=str[i];
}
else
{
word+=str[i];
if(length>longest)
{
longest=length;
maxword=word;
}
length=0;
word="";
}
}
cout << maxword;
return 0;
}
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