Three robbers have come to the left bank of a river.
At the same time, three merchants have come to the right bank of the river.
Each group wants to cross to the opposite side.
1) There is a small raft on the left bank, which can hold only two people.
2) There can never be more robbers than merchants together on the same side.
3) The merchant and robber wearing green clothes are the only ones who can row.
How can they all cross the river?