m=int(input())
a=0
b=0
c=0
for i in range(1,m+1):
if i<=50:
a +=1
elif 50<i<=100:
b +=1
else:
c +=1
tien=a*1500+b*2000+c*2500
print(tien)
bT1pbnQoaW5wdXQoKSkKYT0wCmI9MApjPTAKZm9yIGkgaW4gcmFuZ2UoMSxtKzEpOgoJaWYgaTw9NTA6CgkJYSArPTEKCWVsaWYgNTA8aTw9MTAwOgoJCWIgKz0xCgllbHNlOgoJCWMgKz0xCnRpZW49YSoxNTAwK2IqMjAwMCtjKjI1MDAKcHJpbnQodGllbik=