Sum of Numeric Strings

You are given a list of strings. Each string may represent an integer in a valid format. A string is considered a valid integer if it consists only of an optional '+' or '-' sign followed by one or more digits. Your task is to compute the sum of the valid integer strings and ignore the strings that do not represent a valid integer. For example, the string 7.5 is not valid, but -5 is valid.

Input Format: The input is read from standard input. The first line contains an integer n — the number of strings. The following n lines each contain one string.

Output Format: Output a single integer representing the sum of all valid integer strings.

Note: You must use \( \LaTeX \) format for any formulas. For example, the condition for a valid integer can be written as:

\( \text{Valid if } s \text{ matches } [+-]?\d+ \)

inputFormat

The first line contains an integer ( n ) (( 0 \le n \le 10^5 )), representing the number of strings. Each of the following ( n ) lines contains a non-empty string.

outputFormat

Output a single integer result which is the sum of all valid integer strings from the input.## sample

4
123
456
abc
789

1368