N=gets.to_i;puts N<3?-1:N<4?'a..
a..
.bb':((0..N-4)%4).map{|j|([f=%w(aabc ddbc efgg efhh),%w(affgg axe bxe b.dyy ccdhh),%w(aabc ddbc ..eefg ..hhfg ij..kk ij..ll),%w(ag..g ag..g b.ss.ss bg..g cg..g c.ss.ss .ppqqrr)][N-j-4]||f).map{(?.*j+_1+?.*N)[0,N]}}