Accepted
/in/foo.cc: In function 'void getCatalan()':
/in/foo.cc:31:13: warning: iteration 1000003 invokes undefined behavior [-Waggressive-loop-optimizations]
Catalan[i]=(((Catalan[i-1]*(4*i-2))%mod)*mod_inverse(i+1,mod))%mod;
~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:30:14: note: within this loop
for(ll i=2;i<=maxn;i++){
~^~~~~~
