numList = [5, 12, 13, 22, 9]
i = 0
sum = 0
while i < len(numList): # i is the loop variable
        sum += numList[i]
        i = i + 2
j = 1
k = 20
while j < k: # j and k are loop variables
    print(j, k)
    j += 1
    k -+ 1
#uncomment these to see infinite loops in action
#i = 1
#sum = 0
#while i < 50:
#    sum = sum + 1
#    print(sum)
#i = 0
#sum = 0
#while i != len(numList):
#    sum += numList[i]
#    i = i + 2
