Please Explain this program. I can not able to understand This program

//Here Taka Means Bangladeshi Currency.

a = int(input("Please input your a: "))

b = a
temp = a//1000
print(temp, '1000 Taka note(s).')
if temp > 0:
    a = a%1000
    b = a
else:
    a = b
temp = a//500
print(temp, '500 Taka note(s).')
if temp > 0:
    a = a%500
    b = a
else:
    a = b
temp = a//100
print(temp, '100 Taka note(s).')
if temp > 0:
    a = a%100
    b = a
else:
    a = b
temp = a//50
print(temp, '50 Taka note(s).')
if temp > 0:
    a = a%50
    b = a
else:
    a = b
temp = a//20
print(temp, '20 Taka note(s).')
if temp > 0:
    a = a%20
    b = a
else:
    a = b
temp = a//10
print(temp, '10 Taka note(s).')
if temp > 0:
    a = a%10
    b = a
else:
    a = b
temp = a//5
print(temp, '5 Taka note(s).')
if temp > 0:
    a = a%5
    b = a
else:
    a = b
temp = a//2
print(temp, '2 Taka note(s).')
if temp > 0:
    a = a%2
    b = a
else:
    a = b
temp = a//1
print(temp, '1 Taka note(s).')