第三个WA

n = 0
kw = int(input())
if kw <= 150:
    n += 0.4463 * kw
else:
    n += 0.4463 * 150
if 151 <= kw < 401:
    n += 0.4663 * (kw-150)
else:
    n += 0.4663 * 250
if kw >= 401:
    n += (kw-400) * 0.5663
print('%.1f' % n)