package com.company;

import java.util.Scanner;

public class equalSum {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String[] input = scan.nextLine().split(" ");
        int[] numbers = new int[input.length];
        int length = input.length;

        for (int i = 0; i < length; i++) {
            numbers[i] = Integer.parseInt(input[i]);
        }

        int lefSum = 0;
        int rightSum = 0;
        boolean isEqual = false;
        for (int i = 0; i < length; i++) {
            if (input.length == 1) {
                System.out.println(0);
                isEqual = true;
                break;
            }
            if (i > 0 && lefSum == rightSum) {
                isEqual = true;
                System.out.println(i-1);
                break;
            }
            lefSum = 0;
            rightSum = 0;

            for (int j = 0; j < length; j++) {
                if (i > j) {
                    lefSum += numbers[j];
                } else if (j > i) {
                    rightSum += numbers[j];
                }
            }

        }
        if (!isEqual) {
            System.out.println("no");
        }

    }

}