#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=110;
const int INF=0x3f3f3f3f3f3f3f3f;
int n,m,K,F;
int x[N],y[N],val[N];
int dp[N][N];
int ans=INF;
signed main(){
//	freopen("crystal.in","r",stdin);
//	freopen("crystal.out","w",stdout);
	cin>>n>>m>>K>>F;
	for(int i=1;i<=K;i++)cin>>x[i]>>y[i]>>val[i];
	memset(dp,0x3f,sizeof(dp));
	dp[0][0]=0;
	for(int k=1;k<=K;k++)
		for(int i=n;i>=0;i--)
			for(int j=m;j>=0;j--){
				if(i<x[k]||j<y[k])continue;
				dp[i][j]=min(dp[i][j],dp[i-x[k]][j-y[k]]+val[k]);
			}
	for(int i=0;i<=n;i++)
		for(int j=0;j<=m;j++)
			ans=min(ans,dp[i][j]+F*(abs(n-i)+abs(m-j)));
	cout<<ans<<"\n";
	return 0;
}