Net Balance Calculation

You are given a ledger containing a sequence of transactions. Each transaction is either a credit or a debit transaction accompanied by an amount. Your task is to compute the net balance of the ledger by processing all the transactions.

The net balance is calculated using the formula:

\( \text{net_balance} = \sum_{ i=1}^{t } {\text{amount}_i \times (1 \;\text{if } \text{type}_i = \text{'credit'} \;\text{else} \; -1)} \)

Here, \(t\) is the number of transactions. Each transaction is represented by a type and an amount.

Input Constraints:

• 1 ≤ t ≤ 1000
• Each amount is an integer between 1 and 10000.
• The transaction type is either 'credit' or 'debit'.

inputFormat

The input is given via stdin in the following format:

Line 1: A single integer t, the number of transactions.
Next t lines: Each line contains a string and an integer separated by space. The string represents the transaction type ('credit' or 'debit') and the integer represents the transaction amount.

outputFormat

Output a single integer to stdout which is the net balance after processing all the transactions.

## sample

5
credit 100
debit 50
credit 200
debit 100
credit 150

300