/in/foo.cc: In function 'void splay(int)':
/in/foo.cc:49:18: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  for(int y;y=fa[x];rotate(x))
                  ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:95:8: warning: unused variable 'opt' [-Wunused-variable]
  int n,opt,x,ans=0;
        ^~~
/in/foo.cc:95:12: warning: unused variable 'x' [-Wunused-variable]
  int n,opt,x,ans=0;
            ^
/in/foo.cc:96:14: warning: unused variable 'first' [-Wunused-variable]
  read(n);int first;
              ^~~~~