/in/foo.c: In function 'main':
/in/foo.c:68:6: warning: variable 'nb' set but not used [-Wunused-but-set-variable]
  int nb=1;
      ^~
/in/foo.c:67:6: warning: variable 'na' set but not used [-Wunused-but-set-variable]
  int na=1;
      ^~