# construct empty heap (this is already done in the command interpreter)
c

# insert 20 keys

i 1
i 2
i 3
i 4
i 5
i 6
i 7
i 8
i 9
i 10
i 11
i 12
i 13
i 14
i 15
i 16
i 17
i 18
i 19
i 20

# show heap structure
S

# do 10 extract mins with print key flag off
-
e
e
e
e
e
e
e
e
e
e

# show heap structure
S

# do 10 extract mins with print key flag on
+
e
e
e
e
e
e
e
e
e
e

# show heap structure (should be empty)
S

# do an extract min from empty heap
e

# quit