/in/foo.cc: In function 'int main()':
/in/foo.cc:8:17: warning: unused variable 'a1' [-Wunused-variable]
    8 |     long long n,a1=1,c1=1,k=0,s=0,b1=1;
      |                 ^~
/in/foo.cc:8:22: warning: unused variable 'c1' [-Wunused-variable]
    8 |     long long n,a1=1,c1=1,k=0,s=0,b1=1;
      |                      ^~
/in/foo.cc:8:35: warning: unused variable 'b1' [-Wunused-variable]
    8 |     long long n,a1=1,c1=1,k=0,s=0,b1=1;
      |                                   ^~