#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if (y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if (x < y) x = y; }

int main() {
	int H; int W; int K; int P;
	while (~scanf("%d%d%d%d", &H, &W, &K, &P)) {
		++H, ++W;
		vpii v(K);
		vector<string> names(K);
		rep(i, K) {
			int y; int x;
			scanf("%d%d", &y, &x);
			char buf[101];
			scanf("%s", buf);
			v[i] = { y,x };
			names[i] = buf;
		}
		pair<ll, int> ans(0, 0);
		rep(S, 1 << K) {
			vector<bool> blocked(H * W);
			int pcnt = 0;
			rep(i, K) {
				int y, x;
				tie(y, x) = v[i];
				if (S >> i & 1) {
					++ pcnt;
				} else {
					blocked[y * W + x] = true;
				}
			}
			if (pcnt > P)continue;
			vector<vector<ll>> dp(H, vector<ll>(W));
			if(!blocked[0]) dp[0][0] = 1;
			rep(i, H) rep(j, W) {
				ll x = dp[i][j];
				if (x == 0) continue;
				if (i + 1 < H && !blocked[(i + 1)*W + j])
					dp[i + 1][j] += x;
				if (j + 1 < W && !blocked[i*W + (j+1)])
					dp[i][j + 1] += x;
			}
			amax(ans, make_pair(dp[H - 1][W - 1], S));
		}
		printf("%lld\n", ans.first);
		if (ans.first != 0) {
			rep(i, K) if (ans.second >> i & 1)
				puts(names[i].c_str());
		}
	}
	return 0;
}