#include<bits/stdc++.h>
#define int long long
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
using namespace std;
template<typename T>istream&operator>>(istream&I,vector<T>&v){for(auto&i:v)I>>i;return I;}
template<typename T>ostream&operator<<(ostream&O,vector<T>&v){for(auto&i:v)O<<i<<' ';return O;}
namespace AC{
struct node{
	int x,y;
	string name;
};
void solve(){
	int n,m,k,p;
	cin>>n>>m>>k>>p;
	n++,m++;
	vector<node>v(k);
	for(auto&[x,y,s]:v)cin>>x>>y>>s;
	vector<int>ans;
	int mx=0;
	for(int b=0;b<1<<k;b++){
		if(__builtin_popcount(b)!=p)continue;
		vector<int>tmp;
		vector<vector<int>>dp(n+1,vector<int>(m+1,0));
		for(int i=0;i<k;i++)if((1<<i)&b)tmp.push_back(i);
		else dp[v[i].x][v[i].y]=-1;
		dp[0][0]=1;
		for(int i=0;i<n;i++)for(int j=0;j<m;j++)if(dp[i][j]!=-1){
			if(dp[i+1][j]!=-1)dp[i+1][j]+=dp[i][j];
			if(dp[i][j+1]!=-1)dp[i][j+1]+=dp[i][j];
		}
		if(dp[n-1][m-1]>mx){
			mx=dp[n-1][m-1];
			ans=tmp;
		}
	}
	cout<<mx<<endl;
	for(auto i:ans)cout<<v[i].name<<endl;
}
}
signed main(){
	int t=1;
	//cin>>t;
	while(t--)AC::solve();
}