Problem:
Score : 100 points

Problem Statement

Given is a lowercase English letter C that is not z. Print the letter that follows C in alphabetical order.

Constraints

C is a lowercase English letter that is not z.

Input

Input is given from Standard Input in the following format:

C

Output

Print the letter that follows C in alphabetical order.

Sample Input 1

a

Sample Output 1

b

a is followed by b.

Sample Input 2

y

Sample Output 2

z

y is followed by z.

Solution in Ruby (2.3.3) (judge verdict: Runtime Error)

n, k, m = gets.split.map(&:to_i)
a = gets.split.map(&:to_i)

if (a.sum + k)/n < m
    puts -1
else
    ans = n*m-a.sum
    if ans < 0 
        puts 0
    else
        puts ans
    end
end