#include<bits/stdc++.h>
using namespace std;
const int N=1010;
char g[N][N];
int main()
{
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++)
		{
			cin>>g[i][j];
		}
	}
	bool st=false;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=n;j++)
		{
			if(g[i][j]=='L'&&g[j][i]=='W') continue;
			if(g[i][j]=='W'&&g[j][i]=='L') continue;
			if(g[i][j]=='D'&&g[j][i]=='D') continue;
			if(i==j&&g[i][j]=='-') continue;
			st=true;//存在冲突 
		}
	}
	if(st) cout<<"incorrect";
	else cout<<"correct"; 
	return 0;
}