In case anyone is interested, the non-witty answer would go like this: Clearly, 1+1=2, which is not 3, so ¬(1+1=3) (by usual rules of addition). But also 1+1=3

In case anyone is interested, the non-witty answer would go like this: Clearly, 1+1=2, which is not 3, so ¬(1+1=3) (by usual rules of addition). But also 1+1=3 (by assumption). Since 1+1=3, then either I am the pope, or 1+1=3. But we know that ¬(1+1=3), which means that I must be the pope.