tlylt

Use % 100 to get the last two digits of a number
--- 430 % 100 => 30 
Use // 100 to get the first digit of a number
--- 430 //100 => 4
Use % 10 to get the last digit of a number
--- 430 % 10 => 0
Conclusion
- Use //10 to get from the left
  //10, remove 1 digit from right
  //100, remove 2 digits from right

tlylt

#first
#- write recursive solution
coins = [50, 20, 10, 5, 1]
count =0
count2 = 0
def cc(a,d):
    global count
    count+=1
    if a <0 or d == 0:
        return 0