public static int equalStacks(List<Integer> h1, List<Integer> h2, List<Integer> h3) {
        // Write your code here
        long sum1 = h1.stream().mapToInt(Integer::intValue).sum();
        long sum2 = h2.stream().mapToInt(Integer::intValue).sum();
        long sum3 = h3.stream().mapToInt(Integer::intValue).sum();
        
        Collections.reverse(h1);
        Collections.reverse(h2);
        Collections.reverse(h3);
        
        Stack <Integer> s1 = new Stack<>();
        s1.addAll(h1);
        Stack <Integer> s2 = new Stack<>();
        s2.addAll(h2);
        Stack <Integer> s3 = new Stack<>();
        s3.addAll(h3);
        
        long minHeight;
        while(true){
            if (s1.isEmpty()||s2.isEmpty()||s3.isEmpty()) {
                return 0;
            }
            
            minHeight = Math.min(sum1, Math.min(sum2, sum3));
            
            while (sum1 > minHeight) {
                sum1 -= s1.pop();
            }
            while (sum2 > minHeight) {
                sum2 -= s2.pop();
            }
            while (sum3 > minHeight) {
                sum3 -= s3.pop();
            }
            
            if (sum1 == sum2 && sum2 == sum3) {
                return (int)sum1;
            }
        }
    }