"Perket" is a widely known and delicious meal. For perket to be what it is, cooks must carefully choose the ingredients to get the fullest taste possible while keeping the meal traditional.
You have
As everyone knows, perket is supposed to be neither sour nor bitter; we want to choose the ingredients so that the absolute difference between sourness and bitterness is the smallest.
Also, it is necessary to use at least one ingredient; you can't serve water as the main course.
Input Specification
The first line contains the integer
The input data will be such that, if we make a meal with all ingredients, both the sourness and
bitterness will be less than
Output Specification
Output the smallest possible difference between sourness and bitterness.
Sample Input 1
1
3 10
Sample Output 1
7
Sample Input 2
2
3 8
5 8
Sample Output 2
1
Sample Input 3
4
1 7
2 6
3 8
4 9
Sample Output 3
1
In the third example, we choose the last three ingredients. The total sourness is then
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