public static int equalStacks(List<Integer> h1, List<Integer> h2, List<Integer> h3) {
        
        Stack<Integer> s1 = new Stack<>();
        Stack<Integer> s2 = new Stack<>();
        Stack<Integer> s3 = new Stack<>();
        
        sumStack(s1, h1);
        sumStack(s2, h2);
        sumStack(s3, h3);

        while (true) {
            
            int sum1 = s1.peek();
            int sum2 = s2.peek();
            int sum3 = s3.peek();
            
            if(s1.size() == 0 || s2.size() == 0 || s3.size() == 0) {
                return 0;
            }
            
            if( (sum1 == sum2) && (sum1 == sum3)) {
                return sum1;
            }
            
            Integer minimum = Math.min(sum1, Math.min(sum2, sum3));
            
            while(sum1 > minimum) {

                s1.pop();
                sum1 -= h1.remove(0);
            }
            
            if(s1.isEmpty()) {
                return 0;
            }
            
            while(sum2 > minimum) {
                
                s2.pop();
                sum2 -= h2.remove(0);
            }

            if(s2.isEmpty()) {
                return 0;
            }
            
            while(sum3 > minimum) {
                
                s3.pop();
                sum3 -= h3.remove(0);
            }
            
            if(s3.isEmpty()) {
                return 0;
            }
        }

    }
    
    public static void sumStack(Stack<Integer> s, List<Integer> list) {
        
        int sum = 0;

        for (int i = list.size() - 1; i >= 0 ; i--) {

            Integer currentElement = list.get(i);
            sum += currentElement;
            s.push(sum);
        }
    }