> #include <iostream>
> #include <string>
> #include <stack>
> using namespace std;
> 
> long NextTreeIdentify(string t)
> {
> 	string s,t2,t001("001");
> 	s = t;
> 	long res;
> 	int node,i,posof0,posof001;
> 	bool end = true;
> 	for(i=0;i<=s.size()-3;i++)
> 	{
> 		t2 = s.substr(i,3);
> 		if(t2.compare(t001)==0)
> 		{
> 			posof001 = i;
> 			break;
> 		}
> 	}
> 	end = true;
> 	for(i=posof001+3;i<s.size();i++)
> 	{
> 		if(s[i] != '1')
> 		{
> 			end = false;
> 			break;
> 		}
> 	}
> 
> 	if(!end)
> 	{
> 		/*
> 		s.erase(posof001+1,2);
> 		posof0 = s.find_first_of("0",posof001+1);
> 		s.insert(posof0+1,"1");
> 		s.insert(posof0+1,"0");*/
> 		s.replace(posof001,3,"0");
> 		posof0 = s.find_first_of("0",posof001+1);
> 		s.replace(posof0,1,"001");
> 	}
> 	else
> 	{
> 		s[0] = '0';
> 		for(i=1;i<s.size();i++)
> 		{
> 			if(i%2 == 0)
> 				s[i] = '1';
> 			else
> 				s[i] = '0';
> 		}
> 	}
> 	i = s.size()-1;
> 	res = 0;
> 	while(i>=2)
> 	{
> 		node = s[i]-'0';
> 		if(node == 1)
> 			res +=  node<<i;
> 		i--;
> 	}
> 	return res;
> }
> 
> void doRun()
> {
> 	long res,n,t;
> 	int node;
> 	stack<int> tree;
> 	string s;
> 	scanf("%ld",&n);
> 	if(n == 0||n == 4)
> 	{
> 		res = n;
> 	}
> 	else
> 	{
> 		t = n;
> 		while(1)
> 		{
> 			node = t % 2;
> 			tree.push(node);
> 			if (t<=1)break;
> 			t>>=1;
> 		}
> 		if(tree.size()>30)
> 			return;
> 		while(!tree.empty())
> 		{
> 			s.insert(0,(char*)(tree.top()+'0'));
> 			tree.pop();
> 		}
> 		res = NextTreeIdentify(s);
> 	}
> 	printf("%ld\n",res);
> }
> 
> 
> int main()
> {
> 	//while(1)
> 	doRun();
> 	return 0;
> }
>