SP7676 CPCRC1C - Sum of Digits

Majid is a 3rd-grade elementary student and quite well in mathematics. Once, Majid's teacher asked him to calculate the sum of numbers 1 through n. Majid quickly answered, and his teacher made him another challenge. He asked Majid to calculate the sum of the digits of numbers 1 through n. Majid did finally find the solution. Now it is your turn, can you find a solution?

Two space-separated integers 0

The sum of the digits of numbers a through b.