#include <bits/stdc++.h>
using namespace std;

const double EPS = 1e-9;

int main() {
  double x, y;
  cin >> x >> y;
  size_t n;
  cin >> n;
  vector<double> a(n);
  for (double& a_ : a)
    cin >> a_;

  x = x / 36 * 10;
  y = y / 36 * 10;

  for (size_t i = 0; i < n - 1; i++) {
    double t = a[i] / x;
    if (y * t - a[i + 1] > EPS) {
      puts("NO");
      return 0;
    }
  }
  puts("YES");
  return 0;
}