View Compilation Error

0_0_33710981_16317.cpp: In function 'int main()':
0_0_33710981_16317.cpp:12:9: error: 'll' was not declared in this scope
         ll ans=0;
         ^
0_0_33710981_16317.cpp:18:17: error: 'ans' was not declared in this scope
                 ans+=a;
                 ^
0_0_33710981_16317.cpp:21:20: error: 'ans' was not declared in this scope
         else cout<<ans*W%mod<<endl;
                    ^
0_0_33710981_16317.cpp:21:26: error: 'mod' was not declared in this scope
         else cout<<ans*W%mod<<endl;
                          ^