My submission (8764478) goes wrong on the following tests, but it has an AC on the judge system.

The right answer for all test cases below is "equal".

RRGB GRBR
RRGY GRYR
RRBG BRGR
RRBY BRYR
RRYG YRGR
RRYB YRBR
RGRB BRGR
RGRY YRGR
RGBR GRBR
RGYR GRYR
RBRG GRBR
RBRY YRBR
RBGR BRGR
RBYR BRYR
RYRG GRYR
RYRB BRYR
RYGR YRGR
RYBR YRBR
GRGB BGRG
GRGY YGRG
GGBR BGRG
GGBY BGYG
GGYR YGRG
GGYB YGBG
GBRG BGRG
GBGY YGBG
GBYG BGYG
GYRG YGRG
GYGB BGYG
GYBG YGBG
BRBY YBRB
BGBY YBGB
BBYR YBRB
BBYG YBGB
BYRB YBRB
BYGB YBGB