/in/foo.cc: In function 'int main()':
/in/foo.cc:20:21: warning: unused variable 'pd' [-Wunused-variable]
   20 |                 int pd(i);
      |                     ^~
/in/foo.cc:21:17: warning: 's' may be used uninitialized [-Wmaybe-uninitialized]
   21 |                 if(s==1)
      |                 ^~
/in/foo.cc:16:21: note: 's' was declared here
   16 |         long long n,s,sum=0;
      |                     ^