402178: GYM100687 D Forming Teams (B)

Mr. Ahmad found that in some cases, it is impossible to satisfy everyone. Therefore, some individuals might be assigned to teams.

There are K PCs available at the IT labs, which may be prepared for 1, 2 or 3 students. Find the minimum possible number of unsatisfied students.

The input contains 3 space-separated integers: N M K, where:

N is the number of students who don’t mind to participate individually or in a team of 2 or 3 members.

M is the number of students who chose to participate individually.

K is the number of available PCs in the IT Labs.

All integers are between 0 and 1,000,000,000 (inclusive).

If K PCs are not enough to allow everyone to participate, print -1, otherwise print the minimum number of unsatisfied students.

4 8 8

2

8 5 3

-1

6 3 6

0