#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
template <class T>
inline T read() {
  T x = 0, f = 1;
  char s = getchar();
  while (s < '0' || s > '9') {
    if (s == '-') f = -1;
    s = getchar();
  };
  while (s >= '0' && s <= '9') {
    x = (x << 3) + (x << 1) + s - 48;
    s = getchar();
  };
  return x * f;
}
template <typename T>
inline void wri(T x) {
  if (x < 0) {
    x = -x;
    putchar('-');
  };
  if (x / 10) wri(x / 10);
  putchar(x % 10 + 48);
}
template <typename T>
inline void print(T x, char s) {
  wri(x);
  putchar(s);
}
template <typename T>
T gcd(T a, T b) {
  return b == 0 ? a : gcd(b, a % b);
}
long long p, q;
int n;
long long a[95];
double sum = 0;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  cin >> p >> q >> n;
  for (auto i = (1); i < (n + 1); i++) cin >> a[i];
  long long k = gcd(p, q);
  p /= k, q /= k;
  long long x = 1, y = a[n];
  int flag = 0;
  for (auto i = (n - 1); i >= (1); i--) {
    long long r = y * a[i] + x;
    x = y;
    y = r;
    if (y <= 0) {
      flag = 1;
      break;
    }
  }
  if (!flag && x == q && y == p) {
    cout << "YES";
  } else
    cout << "NO";
  return 0;
}
