Smooth context

Andrii does not like sharp transitions, especially in the context of competitions. Two numbers $a$ and $b$ form a sharp transition if $|a-b|>1$. We say that a competition is smooth if no two neighboring problems create a sharp transition.

You are given $5$ numbers - the difficulty levels of problems. Determine whether these problems form a smooth competition.

Input

The first line contains five integers $a$, $b$, $c$, $d$, $e$ ($1\le a,b,c,d,e\le 10^6$) - the difficulty levels of the problems.

Output

Print «YES» if the numbers form a smooth competition, and «NO» otherwise (the grading system is case-insensitive, so answers like «Yes» and «yES» are also accepted).

Examples

Note

Explanation for the first example:

$|1-2|=1$, $|2-2|=0$, $|2-2|=0$, $|2-1|=1$.

None of these pairs form a sharp transition, so the numbers $1,2,2,2,1$ form a smooth competition.

Explanation for the second example:

$|1-2|=1$, $|2-2|=0$, $|2-1|=1$, $|1-3|=2$.

As we can see, the last two numbers form a sharp transition, so the numbers $1,2,2,1,3$ do not form a smooth competition.