Convert String to Integer

Summary

Convert a numeric string into an integer, handling optional whitespace and sign characters.

Problem statement

Create a function that accepts a string representing an integer and returns its integer value. The input string may include leading or trailing whitespace and an optional '+' or '-' sign. You may assume the string represents a valid integer (no letters or decimal points). Do not print; return the integer.

Task

Write a function that converts a string containing an integer into a Python int.

Examples

Input format

A single string argument is passed to str_to_int(s).

Output format

Return the integer value represented by the string.

Constraints

Input strings are guaranteed to represent valid integers. Use int() conversion and return the result.

Samples