Problems
Farmer John is yet again trying to take a photograph of his
Each cow has an integer "breed ID" number in the range
What is the maximum possible number of groups Farmer John can form?
Input
The first line of input contains
Output
The maximum possible number of groups in Farmer John's photo. It can be shown that at least one feasible grouping exists.
Example #1
7
1 3 5 7 9 11 13
3
In this example, one way to form the maximum number of three groups is as follows. Place 1 and 3 in the first group, 5, 7, and 9 in the second group, and 11 and 13 in the third group.
Example #2
7
11 2 17 13 1 15 3
5
In this example, one way to form the maximum number of five groups is as follows. Place 2 in the first group, 11 in the second group, 13 and 1 in the third group, 15 in the fourth group, and 17 and 3 in the fifth group.