Java adding numbers

String x1 = "3345534534512341999123422 3789234579823475983457321";

add these two numbers together using arrays. CAN NOT USE biginteger must use int only.

Should also work with more than two numbers on a line.

String x2 = "20656 92993021345 4342342 2342342111 0 23134211999"

Example:

3345534534512341999123422 + 3789234579823475983457321 = 7134769100000000000000000

20656 + 92993021345 + 4342342 + 2342342111 + 0 + 23134211999 = 118473938453