Groups and the Group Axioms · Medium problem

Two tables are proposed as the Cayley table of some $4$-element group with identity $e$. Table $P$: row $1$ is $e,a,b,c$; row $2$ is $a,e,c,b$; row $3$ is $b,c,e,a$; row $4$ is $c,b,a,a$. Table $Q$: row $1$ is $e,a,b,c$; row $2$ is $a,b,c,e$; row $3$ is $b,c,e,a$; row $4$ is $c,e,a,b$. One of the two tables cannot be the Cayley table of ANY group, because some row repeats a symbol instead of containing each of $e,a,b,c$ exactly once. In that bad row, how many times does the most-repeated symbol appear?