#include<map>
#include<set>
#include<list>
#include<cmath>
#include<queue>
#include<stack>
#include<cstdio>
#include<string>
#include<vector>
#include<complex>
#include<cstdlib>
#include<cstring>
#include<numeric>
#include<sstream>
#include<iostream>
#include<algorithm>
#include<functional>
 
#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define YES() printf("YES\n")
#define NO() printf("NO\n")
 
using namespace std;
 
#define int long long
//typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      P;
 
const int INF=1e+9;
const double EPS=1e-9;
const int MOD=1000000007;
 
const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};

signed main(){
	int h,w,k,p,ma = 0,maa = 0;
	int dp[34][34];
	string friends[34][34] = {};
	map<string,int> num;
	map<int,string> name;
	cin >> w >> h >> k >> p;
	for(int i = 0;i < k;i++){
		int x,y;
		string s;
		cin >> y >> x >> s;
		friends[x + 1][y + 1] = s;
		num[s] = i;
		name[i] = s;
	}
	for(int i = 0;i < (1 << k);i++){
		int cnt = 0;
		for(int j = 0;j < k;j++){
			if((i >> j) & 1) cnt++;
		}
		if(cnt > p) continue;
		for(int j = 0;j <= h + 1;j++){
			for(int l = 0;l <= w + 1;l++) dp[j][l] = 0;
		}
		dp[0][1] = 1;
		for(int j = 1;j <= h + 1;j++){
			for(int l = 1;l <= w + 1;l++){
				if(friends[j][l] == "" || (i >> (num[friends[j][l]])) & 1){
					dp[j][l] = dp[j][l - 1] + dp[j - 1][l];
				}
			}
		}
		if(ma < dp[h + 1][w + 1]){
			ma = dp[h + 1][w + 1];
			maa = i;
		}
	}
	cout << ma % MOD << endl;
	for(int i = 0;i < k;i++){
		if((maa >> i) & 1){
			cout << name[i] << endl;
		}
	}
	return 0;
}