Roughly four minutes and 20 seconds is the answer, if it's Chun-Li doing most of the dirty work vs. Dante in Marvel vs. Capcom 3. Whoever's playing as Chun-Li wings off another 24 hits to grow on after the combo meter hits 999, too.

You can probably fast forward from about 25 seconds to 4:21 to get the gist of this, unless you really want to hear Chun-Li barking like a pomeranian for four minutes.

Marvel vs Capcom 3: 999-Hit Combo [Shoryuken]