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Input: 2+7+2 (11)
Output: 2+2+2+2+2+2+2(14)
Furthermore Alice, Bob and Charlie likes to get the the same amount out as they put in.
If Bob put 7 BTC in, than he needs to get out 7 BTC - 2 BTC junks for each of them does not work out.
Output: 2+2+2+2+2+2+2(14)