#include<cstdio>
#include<iostream>
#include<string>
#include<cstring>
using namespace std;
string s;
char sta[6000];
int main()
{
	cin>>s;
	int top=0;
	for (int i=0;i<s.size();i++)
	{
		sta[++top]=s[i];
		if (s[i]==')')
		{
			if (sta[top-1]=='(')
				top-=2;			
		}
		else
		{
			if (s[i]==']')
				if (sta[top-1]=='[')
				top-=2;
		}
		
	}
	if (top!=0)
		printf("Wrong");
	else
		printf("OK");
	return 0;
}