mu 1 2 3
mu 3 2 4
mu 3 4 5
mu 4 4 2
mu 2 2 6
mu 2 6 1
pwr 7 3 4
iv 4 6
mu 6 1 7
mu 7 4 1
pwr 5 5 6
iv 6 5
mu 5 2 7
mu 7 6 2