#brainfuck, 45 43 bytes#

>>>,[>,[[<]>[<+>-]>[>]],]<[[>[<+>-]<<]>.<<] 

Shorter, but assumes ',' continues to return 0 after EOF, not just the first time after EOF.

Earlier version:

>>>>>,[>+[<<]+>>->>[>>]+>,]<[[<[<<+>>-]<]<.<] 

Reads numbers as characters, outputs right sum first.

brainfuck, 45 43 bytes

>>>,[>,[[<]>[<+>-]>[>]],]<[[>[<+>-]<<]>.<<] 

Shorter, but assumes ',' continues to return 0 after EOF, not just the first time after EOF.

Earlier version:

>>>>>,[>+[<<]+>>->>[>>]+>,]<[[<[<<+>>-]<]<.<] 

Reads numbers as characters, outputs right sum first.

#brainfuck, 45 bytes#

>>>>>,[>+[<<]+>>->>[>>]+>,]<[[<[<<+>>-]<]<.<] 

Reads numbers as characters, outputs right sum first.

#brainfuck, 45 43 bytes#

>>>,[>,[[<]>[<+>-]>[>]],]<[[>[<+>-]<<]>.<<] 

Shorter, but assumes ',' continues to return 0 after EOF, not just the first time after EOF.

Earlier version:

>>>>>,[>+[<<]+>>->>[>>]+>,]<[[<[<<+>>-]<]<.<] 

Reads numbers as characters, outputs right sum first.