[2, -1, 0, 1, 0, 0]
[1, 2, -2, 0, 1, 0] | 2*II - I
[0, -1, 1, 0, 0, 1]
[2, -1, 0, 1, 0, 0]
[0, 5, -4, -1, 2, 0]
[0, -1, 1, 0, 0, 1] | 5*III + II
[2, -1, 0, 1, 0, 0]
[0, 5, -4, -1, 2, 0] | II + 4*III
[0, 0, 1, -1, 2, 5]
[2, -1, 0, 1, 0, 0]
[0, 5, 0, -5, 10, 20] | II:5
[0, 0, 1, -1, 2, 5]
[2, -1, 0, 1, 0, 0] | I + II
[0, 1, 0, -1, 2, 4]
[0, 0, 1, -1, 2, 5]
[2, 0, 0, 0, 2, 4] | I:2
[0, 1, 0, -1, 2, 4]
[0, 0, 1, -1, 2, 5]
[1, 0, 0, 0, 1, 2]
[0, 1, 0, -1, 2, 4]
[0, 0, 1, -1, 2, 5]