#include <bits/stdc++.h>
using namespace std;

bool check(string s)
{
	stack<char> st;
	for(int i = 0; i < s.size(); ++i)
	{
		if(s[i] == '(' || s[i] == '[' || s[i] == '{' || s[i] == '<')
			st.push(s[i]);
		else if(s[i] == ')')
		{
			if(st.empty()) return false;
			if(st.top() != '(') return false;
			st.pop();
		}
		else if(s[i] == ']')
		{
			if(st.empty()) return false;
			if(st.top() != '[') return false;
			st.pop();
		}
		else if(s[i] == '}')
		{
			if(st.empty()) return false;
			if(st.top() != '{') return false;
			st.pop();
		}
		else if(s[i] == '>')
		{
			if(st.empty()) return false;
			if(st.top() != '<') return false;
			st.pop();
		}
	}
	if(!st.empty()) return false;
	return true;
}
int main()
{
	freopen("check.in","r",stdin);
	freopen("check.out","w",stdout);
	string s;
	cin >> s;
	if(check(s))
	{
		cout << "OK" << endl;
	}
	else
	{
		cout << "Wrong" << endl;
	}
}