/in/foo.cc: In function 'void init()':
/in/foo.cc:41:7: warning: iteration 200009 invokes undefined behavior [-Waggressive-loop-optimizations]
 fac[i]=fac[i-1]*i % mod;
 ~~~~~~^~~~~~~~~~~~~~~~~
/in/foo.cc:40:15: note: within this loop
 for (int i=1;i<=MAXN;i++)
               ^