Read a number without parseInt

Problem

A payment form must read amounts typed by people, without using Integer.parseInt(). Follow these rules exactly:

Skip spaces at the start.
An optional + or - sign may come next.
Read digits until the first character that is not a digit, or the end. Ignore everything after that.
If no digits were read, the value is 0.
If the value is above 2147483647, print 2147483647. If it is below -2147483648, print -2147483648.

Input: One line: the typed text.
Output: One integer: the value.
Constraints: 1 ≤ length of the line ≤ 200
The line has digits, letters, spaces, +, - and . only

Example 1

Input

-42

Output

-42

Leading spaces are skipped, the minus sign is kept.

Example 2

Input

4193 with words

Output

Reading stops at the space after 4193.

Try the problem first. Open one hint at a time.

Hint 1

Use an index i. Move it past spaces, then check for one + or -.

Hint 2

For each digit, value = value * 10 + (ch - '0'), where ch - '0' turns a digit character into its number.

Hint 3

Keep the value in a long and stop as soon as it passes 2147483648, so even 20+ digits cannot overflow the long.

Write your Java code, run it on the examples and submit it to hidden tests.