Problem: The sales department of Japanese Ancient Giant Corp. is visiting a hot spring resort for their recreational trip. For deepening their friendships, they are staying in one large room of a Japanese-style hotel called a ryokan.

In the ryokan, people sleep in Japanese-style beds called futons. They all have put their futons on the floor just as they like. Now they are ready for sleeping but they have one concern: they don’t like to go into their futons with their legs toward heads — this is regarded as a bad custom in Japanese tradition. However, it is not obvious whether they can follow a good custom. You are requested to write a program answering their question, as a talented programmer.

Here let's model the situation. The room is considered to be a grid on an xy-plane. As usual, x-axis points toward right and y-axis points toward up. Each futon occupies two adjacent cells. People put their pillows on either of the two cells. Their heads come to the pillows; their foots come to the other cells. If the cell of some person's foot becomes adjacent to the cell of another person's head, regardless their directions, then it is considered as a bad case. Otherwise people are all right.



Input

The input is a sequence of datasets. Each dataset is given in the following format:

n
x1 y1 dir1
...
xn yn dirn


n is the number of futons (1 ≤ n ≤ 20,000); (xi, yi) denotes the coordinates of the left-bottom corner of the i-th futon; diri is either 'x' or 'y' and denotes the direction of the i-th futon, where 'x' means the futon is put horizontally and 'y' means vertically. All coordinate values are non-negative integers not greater than 109 .

It is guaranteed that no two futons in the input overlap each other.

The input is terminated by a line with a single zero. This is not part of any dataset and thus should not be processed.

Output

For each dataset, print "Yes" in a line if it is possible to avoid a bad case, or "No" otherwise.

Example

Input

4
0 0 x
2 0 x
0 1 x
2 1 x
4
1 0 x
0 1 x
2 1 x
1 2 x
4
0 0 x
2 0 y
0 1 y
1 2 x
0


Output

Yes
No
Yes

Solution (in CPP):

Solution:
#define DEBUG_ON
#define CONDITION false
using namespace std;/*{{{*/

#include <algorithm>
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <sys/time.h>
#include <vector>

#define INF (1e9)
static const double PI = acos(-1.0);
static const double EPS = 1e-10;

typedef long long int LL;
typedef unsigned long long int ULL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<double> VD;
typedef vector<VD> VVD;
typedef vector<bool> VB;
typedef vector<VB> VVB;
typedef vector<char> VC;
typedef vector<VC> VVC;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef complex<double> P;

#define FOR(i, b, e) for (typeof(e) i = (b); i != (e); i < (e)? ++i : --i)
#define REP(i, n) FOR(i, 0, n)

#define IFC(c) if(c) continue;
#define IFB(c) if(c) break;
#define IFR(c, r) if(c) return r;

#define OPOVER(_op, _type) inline bool operator _op (const _type &t) const

#define arrsz(a) ( sizeof(a) / sizeof(a[0]) )

#define F first
#define S second
#define MP(a, b) make_pair(a, b)

#define SZ(a) ((LL)a.size())
#define PB(e) push_back(e)
#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())

#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define EACH(c,it) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define EXIST(s,e) ((s).find(e)!=(s).end())

#define BIT(n) (assert(n < 64), (1ULL << (n)))
#define BITOF(n, m) (assert(m < 64), ((ULL)(n) >> (m) & 1))

#define RANGE(a, b, c) ((a) <= (b) && (b) <= (c))

#define PQ priority_queue
#define SC static_cast

#ifdef DEBUG_ON
	#define dprt(fmt, ...) if (CONDITION) fprintf(stderr, fmt, ##__VA_ARGS__)
	#define darr(a) if (CONDITION) copy( (a), (a) + arrsz(a), ostream_iterator<int>(cerr, " ") ); cerr << endl
	#define darr_range(a, f, t) if (CONDITION) copy( (a) + (f), (a) + (t), ostream_iterator<int>(cerr, " ") ); cerr << endl
	#define dvec(v) if (CONDITION) copy( ALL(v), ostream_iterator<int>(cerr, " ") ); cerr << endl
	#define darr2(a, n, m) if (CONDITION) FOR(i, 0, (n)){ darr_range( (a)[i], 0, (m) ); }
	#define dvec2(v) if (CONDITION) FOR(i, 0, SZ(v)){ dvec( (v)[i] ); }
	#define WAIT() if (CONDITION) { string _wait_; cerr << "(hit return to continue)" << endl; getline(cin, _wait_); }
	#define dump(x) if (CONDITION) cerr << " [L" << __LINE__ << "] " << #x << " = " << (x) << endl;
	#define dumpf() if (CONDITION) cerr << __PRETTY_FUNCTION__ << endl;
	#define dumpv(x) if (CONDITION) cerr << " [L:" << __LINE__ << "] " << #x << " = "; REP(q, (x).size()) cerr << (x)[q] << " "; cerr << endl;
	#define where() if (CONDITION) cerr << __FILE__ << ": " << __PRETTY_FUNCTION__ << " [L: " << __LINE__ << "]" << endl;
	#define show_bits(b, s) if(CONDITION) { REP(i, s) { cerr << BITOF(b, s-1-i); if(i%4 == 3) cerr << ' '; } cerr << endl; }
#else
	#define cerr if(0) cerr
	#define dprt(fmt, ...)
	#define darr(a)
	#define darr_range(a, f, t)
	#define dvec(v)
	#define darr2(a, n, m)
	#define dvec2(v)
	#define WAIT()
	#define dump(x)
	#define dumpf()
	#define dumpv(x)
	#define where()
	#define show_bits(b, s)
#endif

/* Inline functions */
inline int onbits_count(ULL b) { int c = 0; while(b != 0) { c += (b & 1); b >>= 1; } return c; }
inline int bits_count(ULL b) { int c = 0; while(b != 0) { ++c; b >>= 1; } return c; }
inline int toInt(string s) { int v; istringstream sin(s);sin>>v;return v; }
template<class T> inline string toString(T x) { ostringstream sout;sout<<x;return sout.str(); }
inline double now(){ struct timeval tv; gettimeofday(&tv, NULL); return (static_cast<double>(tv.tv_sec) + static_cast<double>(tv.tv_usec) * 1e-6); }
inline VS split(string s, char delimiter) { VS v; string t; REP(i, s.length()) { if(s[i] == delimiter) v.PB(t), t = ""; else t += s[i]; } v.PB(t); return v; }

/* Tweaks */
template<typename T1, typename T2> ostream& operator<<(ostream& s, const pair<T1, T2>& d) {return s << "(" << d.first << ", " << d.second << ")";}

/* Frequent stuffs */
int n_dir = 4;
int dx[] = {0, 1, 0, -1}, dy[] = {-1, 0, 1, 0}; /* CSS order */
enum direction {
	UP, RIGHT, DOWN, LEFT
};
// int n_dir = 8;
// int dx[] = {0, 1, 1, 1, 0, -1, -1, -1}, dy[] = {-1, -1, 0, 1, 1, 1, 0, -1};
// enum direction {
	// UP, UPRIGHT, RIGHT, DOWNRIGHT, DOWN, DOWNLEFT, LEFT, UPLEFT
// }
#define FORDIR(d) REP (d, n_dir)

/*}}}*/

struct futon {
	PII cells[2];
};
vector<futon> futons;
map<PII, PII> opposite;
map<PII, bool> is_head;

bool fix(PII c, bool head)
{
	PII oc = opposite[c];
	is_head[c] = head;
	is_head[oc] = !head;
	bool valid = true;
	REP (d, 4) {
		int y = c.F + dy[d], x = c.S + dx[d];
		IFC (MP(y, x) == oc);
		if (EXIST(opposite, MP(y,x))) {
			if (EXIST(is_head, MP(y, x))) {
				if (is_head[MP(y, x)] != head) {
					return false;
				}
			} else {
				valid = valid && fix(MP(y, x), head);
			}
		}
	}
	REP (d, 4) {
		int y = oc.F + dy[d], x = oc.S + dx[d];
		IFC (MP(y, x) == c);
		if (EXIST(opposite, MP(y,x))) {
			if (EXIST(is_head, MP(y, x))) {
				if (is_head[MP(y, x)] != !head) {
					return false;
				}
			} else {
				valid = valid && fix(MP(y, x), !head);
			}
		}
	}
	return valid;
}

int main()
{
	std::ios_base::sync_with_stdio(false);
	int n;
	while (cin >> n, n) {
		futons.clear();
		opposite.clear();
		is_head.clear();
		REP (i, n) {
			int x, y; cin >> x >> y; char d; cin >> d;
			opposite[MP(y, x)] = MP(y+(d=='y'), x+(d=='x'));
			opposite[MP(y+(d=='y'), x+(d=='x'))] = MP(y, x);
			futon f; f.cells[0] = MP(y, x); f.cells[1] = MP(y+(d=='y'), x+(d=='x'));
			futons.PB(f);
		}
		REP (i, n) {
			PII p = futons[i].cells[0];
			PII op = futons[i].cells[1];
			if (EXIST(is_head, p)) {
				continue;
			}
			// Fix here
			if (!fix(p, true)) {
				goto NO;
			}
		}
YES:
		cout << "Yes" << endl;
		continue;
NO:
		cout << "No" << endl;
	}
}

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