fc=25
units=int(input("enter the no of units:"))
if (units>0 and units<100):
pay=(units*1.5)+fc
print('amount has to pay=',(pay))
elif(units>100 and units<200):
pay=(units*1.5)+(units-100)*2.5+fc+25
print('amount has to pay=',(pay))
elif(units>200 and units<300):
pay=(units*1.5)+(units-100)*2.5+(units-200)*2.5+fc+50
print('amount has to pay=',(pay))
elif(units>300 and units<400):
pay=(units*1.5)+(units-100)*2.5+(units-200)*4+(units-300)*5+fc+75
print('amount has to pay=',(pay))
elif(units>=500):
pay=1500+fc+100
print(pay)
else:
pay=100+fc
print(pay)