EqualSum

import java.util.Scanner;

public class Demo {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        String[] strNumbers = scanner.nextLine().split(" ");

        int[] numbers = new int[strNumbers.length];

        for (int i = 0; i < strNumbers.length; i++) {
            numbers[i] = Integer.parseInt(strNumbers[i]);
        }
        boolean hasEqualSum = false;
        for (int i = 0; i < numbers.length; i++) {
            int leftSum = 0, rightSum = 0;

            for (int j = i - 1; j >= 0 ; j--) {
                leftSum += numbers[j];
            }
            for (int j = i + 1; j < numbers.length; j++) {
                rightSum += numbers[j];
            }

            if(leftSum == rightSum){
                System.out.println(i);
                hasEqualSum = true;
                break;
            }
        }

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