f (0, 0, 0) = 0
f (#, 0, 0) = 0
f (#, 0, aB) = 0
f (#, 0, a9) = a1
f (0, 0, a9) = aB
f (0, a9, a9) = aC
f (a9, a9, 0) = aA
f (a9, a9, a9) = a9
f (#, a1, ?) = a1
f (a1, a9, ?) = a2
f (a9, a9, aA) = aA
f (a9, aA, 0) = 0
f (a2, a9, ?) = a3
f (a3, 0, a9) = a4
f (a3, 0, aC) = aB
f (a3, aB, ?) = a4
f (aB, a9, a9) = a9
f (aA, 0, 0) = 0
f (a1, aC, ?) = a2
f (a2, aC, a9) = a3
f (#, a1, a9) = a1
f (a1, a9, ?) = a2
f (0, aB, 0) = a9
f (0, aA, ?) = a9
f (aA, a9, a9) = a9
f (aC, aA, 0) = 0
f (aB, aC, ?) = a9
f (a9, 0, 0) = 0
f (0, 0, aB) = 0
f (0, aB, aC) = a9
f (aB, aC, a9) = a9
f (aC, a9, aA) = a9
f (a3, 0, aB) = 0
f (a1, a2, ?) = a2
f (a2, a3, a9) = a3
f (a2, a3, aC) = a3
f (a3, 0, 0) = 0
f (a2, 0, 0) = 0
f (a2, 0, a9) = a3
f (a3, aC, aA) = a4
f (a2, 0, aB) = 0
f (a3, aC, a9) = a4
f (0, a9, 0) = 0
f (a1, 0, a9) = a2
f (a2, aC, ?) = a3
f (a3, a9, ?) = a4
f (#, 0, bB) = 0
f (#, 0, b9) = b1
f (0, 0, b9) = bB
f (0, b9, b9) = bC
f (b9, b9, 0) = bA
f (b9, b9, b9) = b9
f (#, b1, ?) = b1
f (b1, b9, ?) = b2
f (b9, b9, bA) = bA
f (b9, bA, 0) = 0
f (b2, b9, ?) = b3
f (b3, 0, b9) = b4
f (b3, 0, bC) = bB
f (b3, bB, ?) = b4
f (bB, b9, b9) = b9
f (bA, 0, 0) = 0
f (b1, bC, ?) = b2
f (b2, bC, b9) = b3
f (#, b1, b9) = b1
f (b1, b9, ?) = b2
f (0, bB, 0) = b9
f (0, bA, ?) = b9
f (bA, b9, b9) = b9
f (bC, bA, 0) = 0
f (bB, bC, ?) = b9
f (b9, 0, 0) = 0
f (0, 0, bB) = 0
f (0, bB, bC) = a9
f (bB, bC, b9) = b9
f (bC, b9, bA) = b9
f (b3, 0, bB) = 0 
f (b1, b2, ?) = b2
f (b2, b3, ?) = b3
f (b3, 0, 0) = 0
f (b2, 0, 0) = 0
f (b2, 0, b9) = b3
f (b3, bC, bA) = b4
f (b2, 0, bB) = 0
f (b3, bC, b9) = b4
f (0, b9, 0) = 0
f (b1, 0, b9) = b2
f (b2, bC, ?) = b3 
f (b3, b9, ?) = b4
f (a9, a9, b9) = b9
f (a9, b9, 0) = E
f (aB, aC, b9) = a9
f (aC, b9, E) = b9
f (bD, E, 0) = 0
f (b1, 0 a9) = a1
f (a2, b9, ?) = b1
f (a2, b1, ?) = b1
f (b1, a1, ?) = a1
f (0, aB, bD) = a9
f (aB, bD, E) = b9
f (0, a9, b9) = bD
f (a1, bD, ?) = b1
f (E, 0, 0) = 0
f (a3, bD, ?) = b1
f (0, b9, a9) = aF
f (b9, a9, 0) = G
f (G, 0, 0) = 0
f (aF, G, 0) = 0
f (0, bB, aF) = b9
f (bB, aF, G) = a9
f (b1, aF, ?) = a1
f (aB, bD, a9) = b9
f (bD, a9, G) = a9
f (a9, G, 0) = 0
f (bD, b9, G) = a9
f (bB, aF, b9) = a9
f (aF, b9, E) = b9
f (a9, b9, a9) = a9
f (b9, a9, b9) = b9
f (b1, a9, ?) = a1
f (a1, b9, ?) = b1
f (aB, bD, b9) = b9
f (bD, b9, bA) = b9
f (a9, b9, b9) = b9
f (bB, aF, a9) = a9
f (0, aB, aC) = a9
f (b9, E, 0) = 0
f (a1, aC, ?) = a2
f (aF, a9, aA) = a9
f (bC, a9, G) = a9
f (b2, a9, ?) = a1
f (a1, 0, bB) = 0
f (a1, 0, b9) = b1
f (b1, 0, aB) = 0
f (b1, 0, a9) = a1
f (b9, a9, a9) = a9
f (b9, b9, a9 ) = a9
f (b2, aF, ?) = a1
f (a2, bD, ?) = b1
f (a3, bD, ?) = b1
f (b2, 0, a9) = a1
f (b3, 0, a9) = a1
f (a2, 0, b9) = b1
f (a3, 0, b9) = b1
f (a3, b1, ?) = b1
f (b2, a1, ?) = a1
f (b3, a1, ?) = a1
f (a1, b1, ?) = b1
f (bB, bC, a9)=b9
f (a2, aC, b9)=a3
f (a3, b9, ?)=b1
f (b4, 0, ?)=0
f (?, a4, ?) = Sa3
f (?, ?, a4) = Sa3
f (a4, ?, ?) = Sa3
f (a4, 0, ?) = 0
f (?, ?, Sa3) = Sa2
f (?, Sa3, ?) = Sa2
f (Sa3, ?, ?) =Sa2
f (Sa3, 0, ?) =0
f (Sa2, ?, ?) = Sa1
f (?, Sa2, ?) = Sa1
f (?, ?, Sa2) = Sa1
f (Sa2, 0, ?) = 0
f (?, Sa1, ?) = 0
f (Sa1, ?, ?) = 0
f (?, b4, ?) = Sb3
f (?, ?, b4) = Sb3
f (?, ?, Sb3) = Sb2
f (?, Sb3, ?) = Sb2
f (Sb3, ?, ?) =Sb2
f (Sb3, 0, ?) =0
f (Sb2, ?, ?) = Sb1
f (?, Sb2, ?) = Sb1
f (?, ?, Sb2) = Sb1
f (Sb2, 0, ?) = 0
f (?, Sb1, ?) = 0
f (Sb1, ?, ?) = 0
f (b4, ?, ?) = Sb3
f (b4, 0, ?) = 0