U11 tt N activate N U21 tt M N s plus activate N activate M and tt X activate X isNat n__0 tt isNat n__plus V1 V2 and isNat activate V1 n__isNat activate V2 isNat n__s V1 isNat activate V1 plus N 0 U11 isNat N N plus N s M U21 and isNat M n__isNat N M N 0 n__0 plus X1 X2 n__plus X1 X2 isNat X n__isNat X s X n__s X activate n__0 0 activate n__plus X1 X2 plus activate X1 activate X2 activate n__isNat X isNat X activate n__s X s activate X activate X X 2.2 U21 tt M N plus activate N activate M isNat n__s V1 activate V1 isNat n__plus V1 V2 and isNat activate V1 n__isNat activate V2 activate n__plus X1 X2 activate X1 plus N 0 U11 isNat N N activate n__isNat X isNat X plus N s M isNat M plus N 0 isNat N isNat n__plus V1 V2 isNat activate V1 U11 tt N activate N activate n__0 0 activate n__plus X1 X2 activate X2 isNat n__s V1 isNat activate V1 plus N s M and isNat M n__isNat N activate n__s X s activate X and tt X activate X plus N s M U21 and isNat M n__isNat N M N isNat n__plus V1 V2 activate V2 U21 tt M N activate N U21 tt M N s plus activate N activate M activate n__plus X1 X2 plus activate X1 activate X2 isNat n__plus V1 V2 activate V1 U21 tt M N activate M activate n__s X activate X true activate n__s X activate X U21 tt M N activate M isNat n__plus V1 V2 isNat activate V1 isNat n__plus V1 V2 activate V1 plus N 0 isNat N activate n__plus X1 X2 plus activate X1 activate X2 plus N s M isNat M U21 tt M N activate N activate n__isNat X isNat X isNat n__plus V1 V2 activate V2 plus N s M U21 and isNat M n__isNat N M N plus N 0 U11 isNat N N activate n__plus X1 X2 activate X1 isNat n__plus V1 V2 and isNat activate V1 n__isNat activate V2 and tt X activate X isNat n__s V1 activate V1 plus N s M and isNat M n__isNat N isNat n__s V1 isNat activate V1 activate n__plus X1 X2 activate X2 U21 tt M N plus activate N activate M U11 tt N activate N true 0 0 0 U21 3 2 3 5857 U11 2 2 0 s 1 1 5855 isNat 1 1 3 activate 1 1 0 and 2 1 2 0 plus 2 1 2 2 activate 1 1 2 n__s 1 1 5855 0 0 2 s 1 0 n__isNat 1 1 2 n__plus 2 1 2 2 n__0 0 2 isNat 1 1 2 plus 2 1 2 2 U11 2 2 3 U21 3 2 3 3 tt 0 3 and 2 1 2 0 isNat n__0 tt activate n__isNat X isNat X plus N s M U21 and isNat M n__isNat N M N U11 tt N activate N and tt X activate X activate n__s X s activate X activate X X isNat n__plus V1 V2 and isNat activate V1 n__isNat activate V2 plus X1 X2 n__plus X1 X2 plus N 0 U11 isNat N N activate n__plus X1 X2 plus activate X1 activate X2 s X n__s X isNat X n__isNat X 0 n__0 activate n__0 0 isNat n__s V1 isNat activate V1 U21 tt M N s plus activate N activate M U21 tt M N s plus activate N activate M false activate n__0 0 false activate n__s X s activate X false NaTT certifiable-1.6