def sum$\_$of$\_$integers$($n$)$:

if n $<1$:

return $0$

i $=1$

sum $=\_\_\_$

while $\_\_\_$:

sum $=$ sum $+$ i

i $=\_\_\_$

return sum

print$($sum$\_$of$\_$integers$(3))$ # should print $6$

print$($sum$\_$of$\_$integers$(4))$ # should print $10$

print$($sum$\_$of$\_$integers$(5))$ # should print $15$