CKM parameter counting ($(N-1{)}^2$)

An $N\times N$ CKM matrix starts with $N^2$ parameters of a unitary matrix. Independent quark rephasings remove $2N-1$ phases because the common phase has no effect. The remaining $(N-1{)}^2$ parameters consist of $N(N-1)/2$ angles and $(N-1)(N-2)/2$ CP-violating phases. Extra mass degeneracies may reduce this generic count.