/in/foo.cc: In function 'int main()':
/in/foo.cc:13:17: warning: iteration 2 invokes undefined behavior [-Waggressive-loop-optimizations]
   all=ceil(n/p[i])*m[i]*2;
              ~~~^
/in/foo.cc:11:15: note: within this loop
  for(int i=1;i<=3;i++)
              ~^~~