int (1-a-b-c) dc db da, c=0 to min((1-a-b)/2,1-2a-b,1-a-2b), b=0 to min((1-a)/2,1-2a), a=0 to 1/2

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.