Smooth contest

Andrey doesn't like sharp drops, especially in contests. Two numbers $a$ and $b$ form a sharp drop if $|a-b|>1$. The competition is considered smooth if no difficulties of two neighboring problems form a sharp drop.

You are given $5$ numbers — the complexity of the problems. Determine if these tasks form a smooth competition.

Input

The first line contains five integers $a$, $b$, $c$, $d$, $e$ ($1\le a,b,c,d,e\le 10^6$) — problem complexity .

Output

Print «YES» if the numbers form a smooth competition, and «NO» otherwise.

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 drop, so the numbers $1,2,2,2,1$ form a smooth contest.

Explanation for the second example: $|1-2|=1$, $|2-2|=0$, $|2-1|=1$, $|1-3|=$2.

As you can see, the last two numbers form a sharp drop, so the numbers $1,2,2,1,3$ do not form a smooth contest.