c-gcc, 125 bytes

Result

WA

Code [DL]

int s[10];int main(){int i=100;while(i--){char c;scanf("%c",&c);s[c-48]++;}for(i=0;i<10;i++){while(s[i]--)printf("%d",i);}}

stdin

8565606845995080651452217324147140812408702727412917647578538893753227368634139471639950978338696080

stdout

stderr

/usr/bin/ld:/volume/CODE: file format not recognized; treating as linker script
/usr/bin/ld:/volume/CODE:1: syntax error
collect2: error: ld returned 1 exit status
/home/esolang/bin/c-gcc: line 4: /tmp/code: No such file or directory

strace