Neighbors of the same sign#7844

Neighbors of the same sign

1 second
128 megabytes
Very easy

Array of integers is given. Print the pairs of adjacent elements of the same sign. If there are no adjacent elements of the same sign, print nothing.

Input

The first line contains number . The next line contains integers. All numbers do not exceed by absolute value.

Output

Print the pairs of adjacent elements of the same sign.

Examples

Example 1

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Example 2

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