Orthogonal

Time Limit : 1 sec, Memory Limit : 65536 KB

𔻒

ʏ̈قȂ 4 _A$A (x_A, y_A)$, $B (x_B, y_B)$, $C (x_C, y_C)$, $D (x_D, y_D)$ ̍WǂݍŁA $AB$ $CD$ ꍇɂ YESAȂꍇɂ NO Əo͂vO쐬ĂBŁAuvƂ͐̂Ƃł͂܂Bȉ̐}QlɂĉB

Input

̃f[^Zbg^܂Bef[^Zbǧ͈ȉ̂ƂłB

$x_A$ $y_A$ $x_B$ $y_B$ $x_C$ $y_C$ $x_D$ $y_D$

$x_A$, $y_A$, $x_B$, $y_B$, $x_C$, $y_C$, $x_D$, $y_D$ ͂ꂼ -100 ȏ 100 ȉłAel͏_ȉő 5 ܂ł̐܂ގŗ^܂B

f[^Zbg̐ 100 𒴂܂B

Output

ef[^Zbgɑ΂āAYES ܂ NO Psɏo͂ĉB

Sample Input

1.0 1.0 2.0 2.0 0.0 0.0 1.0 -1.0
0.0 0.0 2.0 0.0 -1.0 2.0 2.0 2.0
10.0 6.0 3.4 5.2 6.8 9.5 4.3 2.1
2.5 3.5 2.5 4.5 -3.3 -2.3 6.8 -2.3


Output for the Sample Input

YES
NO
NO
YES
`

Source: PC Koshien 2004 , All-Japan High School Programming Contest, Aizu-Wakamatsu, Japan, 2004
http://www.pref.fukushima.jp/pc-concours/