cerc07p.cpp

// 2008-09-26
#include <iostream>
#include <algorithm>
#ifdef ONLINE_JUDGE
#define gc getchar_unlocked
#else
#define gc getchar
#endif
int in()
{
	char c;
	int res=0;
	bool minus=false;
	for(;;)
	{
		c=gc();
		if (c=='-')
			minus=true;
		else if (c<=32)
			return minus?-res:res;
		else
			res=(res<<1)+(res<<3)+c-'0';
	}
}
using namespace std;
int main()
{
	pair<pair<int,int>,int> A[1000];
	pair<pair<int,int>,int> B[1000];
	int px[1000];
	int py[1000];
	int nx[1000];
	int ny[1000];
	bool up[1000];
	bool right[1000];
	char res[1000];
	int N,i;
	for(;;)
	{
		N=in();
		if (!N) return 0;
		for (i=0; i<N; i++)
		{
			A[i].first.first=B[i].first.second=px[i]=in();
			B[i].first.first=A[i].first.second=py[i]=in();
			A[i].second=B[i].second=i;
		}
		gc();
		sort(A,A+N);
		sort(B,B+N);
		for (i=0; i<(N>>1); i++)
		{
			ny[A[i<<1].second]=A[(i<<1)+1].second;
			up[A[i<<1].second]=true;
			ny[A[(i<<1)+1].second]=A[i<<1].second;
			up[A[(i<<1)+1].second]=false;
			nx[B[i<<1].second]=B[(i<<1)+1].second;
			right[B[i<<1].second]=true;
			nx[B[(i<<1)+1].second]=B[i<<1].second;
			right[B[(i<<1)+1].second]=false;
		}
		int cnt=0;
		int firstpoint;
		bool v=true;
		int point=A[0].second;
		while (cnt<N)
		{
			if (!point)
				firstpoint=cnt;
			if (v)
			{				
				if (up[point])
					res[cnt++]='N';
				else
					res[cnt++]='S';
				v=false;
				point=ny[point];
			}
			else
			{
				if (right[point])
					res[cnt++]='E';
				else
					res[cnt++]='W';
				v=true;
				point=nx[point];
			}
		}
		for (i=firstpoint; i<N; i++)
			putchar(res[i]);
		for (i=0; i<firstpoint; i++)
			putchar(res[i]);
		putchar('\n');
	}
	return 0;
}