#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <algorithm>
#include <atcoder/all>
#include <bitset>
#include <cassert>
#include <cmath>
#include <ctime>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--)
#define repk(i, k, n) for (int i = k; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
#define mod3 100000007
#define vi vector<int>
#define vs vector<string>
#define vc vector<char>
#define vl vector<ll>
#define vb vector<bool>
#define vvi vector<vector<int>>
#define vvc vector<vector<char>>
#define vvl vector<vector<ll>>
#define vvb vector<vector<bool>>
#define vvvi vector<vector<vector<int>>>
#define vvvl vector<vector<vector<ll>>>
#define pii pair<int, int>
#define pil pair<int, ll>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int, int>>
#define vpll vector<pair<ll, ll>>
#define vvpii vector<vector<pair<int, int>>>
#define vvpll vector<vector<pair<ll, ll>>>

template <typename T>
void debug(T e) {
    cerr << e << endl;
}

template <typename T>
void debug(vector<T> &v) {
    rep(i, v.size()) { cerr << v[i] << " "; }
    cerr << endl;
}

template <typename T>
void debug(vector<vector<T>> &v) {
    rep(i, v.size()) {
        rep(j, v[i].size()) { cerr << v[i][j] << " "; }
        cerr << endl;
    }
}

template <typename T>
void debug(vector<pair<T, T>> &v) {
    rep(i, v.size()) { cerr << v[i].first << " " << v[i].second << endl; }
}

template <typename T>
void debug(set<T> &st) {
    for (auto itr = st.begin(); itr != st.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(multiset<T> &ms) {
    for (auto itr = ms.begin(); itr != ms.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(map<T, T> &mp) {
    for (auto itr = mp.begin(); itr != mp.end(); itr++) {
        cerr << itr->first << " " << itr->second << endl;
    }
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << H << " ";
    debug_out(T...);
}

int main() {
    ll H, W, K, P;
    cin >> H >> W >> K >> P;
    vector<ll> x(K);
    vector<ll> y(K);
    vector<string> N(K);
    for (ll i = 0; i < K; i++) {
        cin >> x[i] >> y[i] >> N[i];
    }
    ll max_val = 0;
    ll max_idx = -1;
    for (ll i = 0; i < (1 << K); i++) {
        ll popcnt = 0;
        vector<vector<bool>> pos(H + 1, vector<bool>(W + 1, true));
        for (ll j = 0; j < K; j++) {
            if (!((i >> j) & 1)) {
                pos[x[j]][y[j]] = false;
            } else {
                popcnt++;
            }
        }
        if (popcnt > P) {
            continue;
        }
        vector<vector<ll>> dp(H + 1, vector<ll>(W + 1, 0));
        dp[0][0] = 1;
        for (ll j = 0; j <= H; j++) {
            for (ll k = 0; k <= W; k++) {
                if (j < H) {
                    if (pos[j + 1][k]) {
                        dp[j + 1][k] += dp[j][k];
                    }
                }
                if (k < W) {
                    if (pos[j][k + 1]) {
                        dp[j][k + 1] += dp[j][k];
                    }
                }
            }
        }
        if (max_val < dp[H][W]) {
            max_val = dp[H][W];
            max_idx = i;
        }
    }
    if (max_val == 0) {
        cout << 0 << endl;
        return 0;
    }
    cout << max_val << endl;
    for (ll i = 0; i < K; i++) {
        if ((max_idx >> i) & 1) {
            cout << N[i] << endl;
        }
    }
}