Making three-digit numbers

cards holds the digits written on number cards. You pick three of the cards, each card at most once, and put them in a row to make a three-digit number. The first digit cannot be 0.

Complete the function solution, which returns how many different three-digit numbers you can make. Several cards may have the same digit.

Function

solution(cards)

Constraints

• The length of cards is from 3 to 10.
• The digit on each card is an integer from 0 to 9.

Examples

Starter code

def solution(cards):
    answer = 0
    return answer