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Competitions

# Odd sum

Given n pairs of positive integers. Count number of ways to choose exactly one number from each pair such that the sum of those numbers is odd.

#### Input

First line contains number of pairs n. Each of the next n lines contains one pair of positive integers.

#### Output

Print the required number of ways, which does not exceed 1018.

Time limit 1 second
Memory limit 128 MiB
Input example #1
3
1 2
3 5
4 1

Output example #1
4