Unable to read single character in Java
<p>I wrote this code based on an example I found:</p>

<pre><code>do {
    System.out.print("¿What kind of envelope do you want? (A)Mini B)Midi C)Maxi): ");
    cadena = sc.next();
    tipo = cadena.charAt(0);
    tipo=Character.toUpperCase(tipo);
} while (tipo != 'A' || tipo != 'B' || tipo != 'C');
</code></pre>

<p>But it keeps asking me constantly the kind of envelope instead of registering my choice.
What am I doing wrong and how can I solve it?</p>
