Puzzle 8990: obvious but tricky

i think i've seen this before!

Author:	csgroup11
Date posted:	11/22/2016 2:05:20 AM
Difficulty (1..5):	1.24 (25 votes)
Popularity:	11 (18 liked, 7 disliked)
Correct solution submitted:	231

Solved by 156 players

_nick (4)	360506 (4)	362171 (4)	404225 (4)	408890 (4)
411209 (4)	413064 (4)	419513 (4)	420792 (4)	422435 (4)
423278 (4)	423398 (4)	428262 (4)	428409 (4)	428994 (4)
429102 (4)	430196 (4)	430479 (4)	442495 (4)	452900 (4)
46324100 (4)	463318 (4)	472225 (4)	475043 (4)	475153 (4)
476445 (4)	483273 (4)	483945 (4)	484573 (4)	484936 (4)
485807 (4)	501021 (4)	antonbootsma (4)	arkangelsk1 (4)	axorion (4)
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hero (4)	Inconight (4)	jnpollack (4)	kowka_z (4)	lalala (4)
onqt (4)	padre (4)	pento (4)	ppetrov (4)	scifista42 (4)
scorpio (4)	smylic (4)	sungyeonpark (4)	tadano (4)	TimThree (4)
tiyo (4)	xbox_rob (4)	420227 (5)	496472 (5)	1234alberto (6)
365642 (6)	408771 (6)	413937 (6)	485536 (6)	9651410232 (6)
aja2718 (6)	ajayjha25 (6)	alatristecap (6)	amazed (6)	Anabirelle (6)
Angrevol (6)	atzame (6)	benjaminRR (6)	beseech (6)	ceecee (6)
davenger (6)	Davoust (6)	DonDiego2000 (6)	drwatson (6)	EchelonBCN (6)
Egorovsasa (6)	eversyt (6)	eyTns (6)	Fifiasokon (6)	filiep (6)
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jhnesk (6)	KeyoN (6)	kraker (6)	kserikba (6)	leesangwook (6)
libbyhyry (6)	lka_76 (6)	maruska (6)	Meddaif99 (6)	milusheva (6)
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363699 (7)	420829 (7)	421850 (7)	carrben12 (7)	Chirector (7)
dmmn (7)	dougheim (7)	emmagineif (7)	JackHarkness23 (7)	NoThlnG (7)
Ptolo (7)	Rondholz (7)	ssancho (7)	432796 (8)	435027 (8)
451139 (8)	483119 (8)	500974 (8)	502706 (8)	belenus (8)
csgroup11 (8)	Dharavi (8)	drmazhar (8)	giridhar1202 (8)	Jumao (8)
leokaiser (8)	lordofdead38 (8)	qwertymol (8)	silver (8)	twoflower (8)
ym1029sun (8)

Number of commands in the solution is shown in brackets. Shown as ? when not available.