Xiaoyu's Electricity Bill

Problem Source

Luogu P1422

Problem Description

Summer is here, and every household is using far more electricity — and paying far more for it. Xiaoyu's family received an electricity bill today. It reads: according to the regulation Min Dian Jia [2006] No. 27, the tiered pricing is as follows:

• For the portion of monthly usage up to and including $150$ kWh: $0.4463$ yuan per kWh;
• For the portion between $151$ and $400$ kWh: $0.4663$ yuan per kWh;
• For the portion of $401$ kWh and above: $0.5663$ yuan per kWh.

Xiaoyu wants to check whether the billed amount is correct. Write a program that, given the total electricity used, computes the bill according to these rates.

Input Format

The input is a single positive integer: the total electricity used (in kWh), not exceeding $10000$.

Output Format

Output one number, kept to 1 decimal place (in yuan, kept to 1 decimal place).

Sample Input

267

Sample Output

121.5

Hint

• The three tiers are additively accumulated: each tier only charges for the part of the usage that falls within that tier's band — you do not compute the whole usage at a single tier's rate.
• First break the sample down on paper (how does 267 kWh split into two bands?) before writing code.
• Keep 1 decimal place.