#include <bits/stdc++.h>
using namespace std;
unsigned long long GCD(unsigned long long num1, unsigned long long num2) {
  if (num2 == 0) return num1;
  return GCD(num2, num1 % num2);
}
int main() {
  unsigned long long p, q;
  cin >> p >> q;
  int n;
  cin >> n;
  unsigned long long a[n];
  for (int i = 0; i < n; i++) cin >> a[i];
  if (n == 1) {
    if (p % q == 0 && p / q == a[0]) {
      puts("YES");
    } else {
      puts("NO");
    }
  } else {
    if (p / q < a[0]) {
      puts("NO");
      return 0;
    }
    unsigned long long k = GCD(p, q);
    p /= k;
    q /= k;
    unsigned long long p_ = 1, q_ = a[n - 1];
    unsigned long long aux;
    for (int i = n - 2; i > 0; i--) {
      p_ += q_ * a[i];
      aux = p_;
      p_ = q_;
      q_ = aux;
    }
    p_ += q_ * a[0];
    if (p == p_ && q == q_) {
      puts("YES");
      return 0;
    }
    puts("NO");
  }
  return 0;
}
