Explain how you derived its complexity of the given algorithm. $($Normally$,$ this explanation involves identifying its characteristic operation, expressing as a summation the number of times the characteristic operation is executed, and simplifying the summation.$)$

#check pre$-$conditions

if isEmpty$($inputList$)$:

# if invalid input

print$("$Invalid input"$)$

return

n $=$ length$($inputList$)$

#iterate through all possible combinations of three elements

for i from $0$ to $($n $-3)$:

for j from $($i $+1)$ to $($n $-2)$:

for k from $($j $+1)$ to $($n $-1)$:

#print the current subset of three elements

print$($inputList$[$i$],$ inputList$[$j$],$ inputList$[$k$])$on$.)$