n = int(input())
for i in range (1,n+1):
    sum = 0
    a = int(input())
    b = int(input())
    if a%2==1:
        for j in range(a,b+1,2):
            sum += j
    else:
        for j in range(a+1,b+1,2):
            sum += j
    print("Case "+str(i)+": "+str(sum))