rail, 140 bytes

Result

AC

Code [DL]

$ 'j'      #(c){j}(x)-@
 \-(!x!)(!c!)(c)(x)g<
              #(x)(c)-@
$ 'main'@
 \@      \-uo--
 | \{j}i- \    >#
 9  \    >u-1q/
 \-1a--e/

stdin

9050868233414064668198263279581380097497444442415820921527061219581404091700330298990809844125745087

stdout

0000000000000001111111111222222222233333344444444444444455555556666667777777888888888888999999999999

stderr

strace