/in/foo.cc: In function 'int main()':
/in/foo.cc:15:9: warning: iteration 100004 invokes undefined behavior [-Waggressive-loop-optimizations]
   two[i]=(two[i-1]<<1)%mod;
   ~~~~~~^~~~~~~~~~~~~~~~~~
/in/foo.cc:14:15: note: within this loop
  for(int i=1;i<=100005;i++){
              ~^~~~~~~~