public static String fairRations(List<Integer> B) {
    List<Integer> ration = new ArrayList<>(B);
    int count = 0;
    for(int i=0 ;i< ration.size()-1; i++) {
        if(ration.get(i) % 2 == 0) continue;
        if(ration.get(i) % 2 != 0) {
            ration.set(i, ration.get(i)+1);
            ration.set(i+1, ration.get(i+1)+1);
            count += 2;
        }
    }
    if(ration.get(ration.size()-1)%2 != 0) return "NO";
    return ""+count;
}