ach[7], chi[7], ich[7], duc[6], hai[4], iah[4], hau[4], hui[4], dad[3], dia[3], dau[3],
ah[3], ha[3], hi[3], hu[3], uh[3], ad[2], da[2], ai[2], au[2], du[2], ud[2], ui[2],
