제출 #27774

5
size
pop
back
empty
front

0
-1
-1
0
-1

0
-1
-1
1
-1

5
empty
empty
front
size
pop

0
0
-1
0
-1

1
1
-1
0
-1

5
empty
pop
front
push 448
push 689

0
-1
-1

1
-1
-1