import java.io.OutputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.Arrays; import java.util.StringTokenizer; import java.io.IOException; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.InputStream; /** * Built using CHelper plug-in * Actual solution is at the top * * @author Chiaki.Hoshinomori */ public class Main { public static void main(String[] args) { InputStream inputStream = System.in; OutputStream outputStream = System.out; InputReader in = new InputReader(inputStream); PrintWriter out = new PrintWriter(outputStream); Task496 solver = new Task496(); solver.solve(1, in, out); out.close(); } static class Task496 { public void solve(int testNumber, InputReader in, PrintWriter out) { int n = in.nextInt(); int m = in.nextInt(); int q = in.nextInt(); int f = in.nextInt(); int[][] dp = new int[n + 1][]; for (int i = 0; i <= n; ++i) { dp[i] = new int[m + 1]; Arrays.fill(dp[i], 1000000000); } dp[0][0] = 0; for (int i = 0; i < q; i++) { int x = in.nextInt(); int y = in.nextInt(); int z = in.nextInt(); for (int a = n; a >= x; --a) { for (int b = m; b >= y; --b) { dp[a][b] = Math.min(dp[a][b], z + dp[a - x][b - y]); } } } int ret = (n + m) * f; for (int i = 0; i <= n; ++i) { for (int j = 0; j <= m; ++j) { ret = Math.min(ret, dp[i][j] + Math.abs(n - i) * f + Math.abs(m - j) * f); } } out.println(ret); } } static class InputReader { public BufferedReader reader; public StringTokenizer tokenizer; public InputReader(InputStream stream) { reader = new BufferedReader(new InputStreamReader(stream), 32768); tokenizer = null; } public String next() { while (tokenizer == null || !tokenizer.hasMoreTokens()) { try { tokenizer = new StringTokenizer(reader.readLine()); } catch (IOException e) { throw new RuntimeException(e); } } return tokenizer.nextToken(); } public int nextInt() { return Integer.parseInt(next()); } } }