bash-pure, 49 bytes

Result

WA

Code [DL]

f()(a[c]+=$c;read -n1 c&&f);f
IFS=;echo "${a[*]}"

stdin

9909180865628578835574310195791354508761623230816597371132658506220930992474014538500011636748666686

stdout

stderr

/bin/bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)

strace