/in/foo.cc: In function 'int main()':
/in/foo.cc:22:24: warning: iteration 200000 invokes undefined behavior [-Waggressive-loop-optimizations]
  For(i, 1, N) if(!Log[i]) Log[i] = Log[i - 1];
                   ~~~~~^
/in/foo.cc:4:39: note: within this loop
 #define For(i, l, r) for(int i = l; i <= r; ++i)
                                        
/in/foo.cc:22:6:
  For(i, 1, N) if(!Log[i]) Log[i] = Log[i - 1];
      ~~~~~~~                           
/in/foo.cc:22:2: note: in expansion of macro 'For'
  For(i, 1, N) if(!Log[i]) Log[i] = Log[i - 1];
  ^~~