#CCBOTPBA0000032. Chuỗi tăng theo chữ số (Strictly Increasing Digits)

Chuỗi tăng theo chữ số (Strictly Increasing Digits)

Strictly Increasing Digits

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Check whether every successive decimal digit is strictly larger than its predecessor, read left to right; one-digit values qualify.

Input

One integer n.

Output

Print YES or NO.

Subtasks

  • Subtask 1 (20%): n ≤ 999.

  • Subtask 2 (30%): n ≤ 10^9.

  • Subtask 3 (50%): n ≤ 10^18.

Examples

Example 1

Input:

12359

Output:

YES

Explanation: The digits satisfy 1<2<3<5<9.

Example 2

Input:

112

Output:

NO

Explanation: The adjacent ones are equal, violating strict increase.

Example 3

Input:

0

Output:

YES

Explanation: Zero contains only one digit.