/in/foo.cc: In function 'int main()':
/in/foo.cc:16:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
/in/foo.cc:17:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  For(i,1,n) scanf("%d",&a[i]);
                              ^
/in/foo.cc:18:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  For(i,1,n) scanf("%d",&b[i]);
                              ^