C$++,$ INPUT INTO A VECTOR NOT ARRAY.

Write a program that stores a list of positive integers from input into a vector and outputs the Nth number from the end of the vector. A negative integer indicates the end of the input and is not stored in the vector. Convert the negative integer read at the end to positive and use as N$.$ Output the negative integer read at the end if the size of the vector is smaller than N$.$ Assume the vector will always contain fewer than $20$ integers.

Ex: If the input is:

$15975-3$

the output is:

$9$

Ex: If the input is:

$12345-6$

the output is:

$-6$