#include<bits/stdc++.h>
using namespace std;
//输入保证正确
//输出看仔细
//所有情况都测
//数组定义，保证正确
string s;
bool check(string s1,string s2)
{
	int f = 0,zs2=0,xs2=0,f1=0,f2=0;
	for(int i = 0;i < s1.size();i ++)
	{
		if(s1[i]=='.')
		{
			f1=i;
		}
	}
	for(int i = 0;i < s2.size();i ++)
	{
		if(s2[i]=='.')
		{
			f2=i;	
		}
	}
	if(f1==0)
		f1=s1.size();
	if(f2==0)
		f2=s2.size();
	if(f1!=f2)
		return f1<f2;
	for(int i = 0;i < f1;i ++)
	{
		if(s1[i]<s2[i])
			return true;
		if(s1[i]>s2[i])
			return false;
	}
	for(int i = f1+1;i < min(s1.size(),s2.size());i ++)
	{
		if(s1[i]<s2[i])
			return true;
		if(s1[i]>s2[i])
			return false;
	}
	return s1.size()<s2.size();
}
int main()
{
	getline(cin,s);
	string t = "" , ma="";
	s=s+'!';
	for(int i = 0;i < s.size();i++)
	{
		if(isdigit(s[i])||s[i]=='.')
			t=t+s[i];
		else
		{
			if(t!=""&&check(ma,t))
				ma=t;
			t="";
		}
//		cout<<t<<" ";
	}
	cout<<ma;
 	return 0;
}