/in/foo.cc: In function 'int main()':
/in/foo.cc:13:2: error: expected ',' or ';' before 'scanf'
  scanf("%d",&k);
  ^~~~~
/in/foo.cc:32:17: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
  printf("%d",ans);
                 ^