comb[1]=[1,4,7]
comb[2]=[1,4,3]
comb[3]=[1,5,7]
comb[4]=[1,5,3]
comb[5]=[2,4,7]
comb[6]=[2,4,3]
comb[7]=[2,5,7]
comb[8]=[2,5,3]
comb[9]=[6,4,7]
comb[10]=[6,4,3]
comb[11]=[6,5,7]
comb[12]=[6,5,3]