/in/foo.cc: In function 'int main()':
/in/foo.cc:10:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  printf("%d",n-(n>>1)+(n+1>>1)-((n-1)/3+1>>1));
                        ~^~
/in/foo.cc:10:40: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  printf("%d",n-(n>>1)+(n+1>>1)-((n-1)/3+1>>1));
                                 ~~~~~~~^~
/in/foo.cc:8:8: warning: unused variable 'ans' [-Wunused-variable]
  int n,ans=0;
        ^~~