package chelper;

import java.util.Arrays;

import io.InputReader;
import io.OutputWriter;
import misc.GCJSolution;
import misc.SimpleSavingChelperSolution;


public class TaskB extends GCJSolution {

  private int m;
  private long total;
  private int n;
  private int[] cap;
  private long[] per;
  private long[] c;

  public void solve(int testNumber, InputReader in, OutputWriter out) {
    wrapSolve(testNumber, in, out);
  }

  long get(long time) {
    long[] g = new long[n];
    
    for (int i = 0; i < n; i++) {
      g[i] = Math.min(Math.max(0, time - c[i]) / per[i], cap[i]);
    }

    Arrays.sort(g);

    long res = 0;
    for (int i = 0; i < m; i++) {
      res += g[n - i - 1];
    }

    return res;
  }

  @Override
  public void solve(int testNumber) {
    m = in.nextInt();
    total = in.nextLong();
    n = in.nextInt();

    cap = new int[n];
    per = new long[n];
    c = new long[n];

    for (int i = 0; i < n; i++) {
      cap[i] = in.nextInt();
      per[i] = in.nextLong();
      c[i] = in.nextLong();
    }

    long l = 0;
    long r = Long.MAX_VALUE / 3;

    while (r - l > 1) {
      long m = (l + r + 1) / 2;

      long x = get(m);

      if (x < total) {
        l = m;
      } else {
        r = m;
      }
    }

    out.println(r);
  }
}