import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Arrays; import java.util.stream.Stream; import static java.lang.System.in; public class Main { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(in)); String[] inputs = reader.readLine().split(" "); int X = Integer.parseInt(inputs[0]); int Y = Integer.parseInt(inputs[1]); double X1 = X * 1000 / 3600.0; double Y1 = Y * 1000 / 3600.0; int N = Integer.parseInt(reader.readLine()); inputs = reader.readLine().split(" "); boolean canChase = true; int[] intersections = Stream.of(inputs).mapToInt(Integer::parseInt).toArray(); for (int i = 0; i < N; i++) { int intersection = Integer.parseInt(inputs[i]); double time = intersection / X1; double masterPosition = time * Y1; for (int j = i + 1; j < N; j++) { if (masterPosition > intersections[j]) { canChase = false; break; } } if (!canChase) { break; } } if (canChase) { System.out.println("YES"); } else { System.out.println("NO"); } } }