Challenge: fastest program wins

Write a program in your language that
1.opens a file as arbitrary precision integer.
2.divides the number by 3.
3.stores the binary result in another file.

Benchmark with one-megabyte file:

$ time python3.0 16.py in.txt out.txt

real    1m14.621s
user    1m11.377s
sys    0m2.338s
$ time java Lol /* 20 */

real    0m45.685s
user    0m43.816s
sys    0m1.308s
$ time ./23 in.txt out.txt

real    0m2.834s
user    0m2.114s
sys    0m0.157s
$ time ./35 in.txt out.txt

real    0m0.049s
user    0m0.037s
sys    0m0.010s