system "mv nkf.in nkf.in.$error_count.bad";
system "mv nkf.out nkf.out.$error_count.bad";
open(OUT,"> nkf.expect.$error_count.bad");
system "mv nkf.in nkf.in.$error_count.bad";
system "mv nkf.out nkf.out.$error_count.bad";
open(OUT,"> nkf.expect.$error_count.bad");