BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str[] = br.readLine().split(" ");
        int side[] = new int[3];
        int sum = 0;
        boolean tri = true;
        for (int i=0; i<3; i++) {
            side[i] = Integer.parseInt(str[i]);
            sum += side[i];
        }
        double sum2 = sum;
        for (int i=0; i<3; i++) {
            if (sum2/2-side[i]<=0) {
                tri = false;
            }
        }
        if (tri) {
            System.out.println("yes");
        } else {
            System.out.println("no");
        }