2654. What character can be added to both of these characters to give other characters? 日_ -> _長

日  NICHI, JITSU, hi, ka - sun, day

長  CHOU, naga(i) - long

Add 月:日+月 月+長   

月  GETSU, GATSU, tsuki - moon, month

明  MEI, MYOU, aka(rui), a(keru) - bright

脹  CHOU - swell