// Arup Guha
// 3/5/2022
// Solution to 2021 SER D2 Problem: Average Character

import java.util.*;

public class average {
	
	public static void main(String[] args) {

		// Get the whole line.
		Scanner stdin = new Scanner(System.in);
		String line = stdin.nextLine();
		
		// Sum character values.
		int sum = 0;
		for (int i=0; i<line.length(); i++)
			sum += (int)(line.charAt(i));
			
		// Use integer division and output.
		int avg = sum/line.length();
		System.out.printf("%c\n", avg);
	}
}