#include <bits/stdc++.h>
int main() {
  int t = 1, i, j, n;
  long long int p, q, temp, arr[90];
  for (j = 0; j < t; j++) {
    scanf("%lld %lld", &p, &q);
    scanf("%d", &n);
    for (i = 0; i < n; i++) scanf("%lld", &arr[i]);
    for (i = 0; i < n; i++) {
      if (p / q < arr[i]) {
        printf("NO\n");
        break;
      }
      p = p - (q * arr[i]);
      if (p == 0 && i != n - 1) {
        printf("NO\n");
        break;
      }
      if (i != n - 1) {
        temp = p;
        p = q;
        q = temp;
      }
    }
    if (p == 0 && i == n)
      printf("YES\n");
    else if (i == n)
      printf("NO\n");
  }
  return 0;
}
