View Compilation Error

0_0_25921942_20005.cpp: In function 'int main()':
0_0_25921942_20005.cpp:51:13: error: 'll' was not declared in this scope
             ll ans=C(k,m+k-1);
             ^
0_0_25921942_20005.cpp:52:29: error: 'ans' was not declared in this scope
             printf("%lld\n",ans);
                             ^
0_0_25921942_20005.cpp:55:13: error: 'll' was not declared in this scope
             ll ans=C(m-1,m+k-1);
             ^
0_0_25921942_20005.cpp:58:17: error: 'ans' was not declared in this scope
                 ans+=flag*C(i,m)*C(m-1,m+k-i*n-1)%mod;
                 ^
0_0_25921942_20005.cpp:62:29: error: 'ans' was not declared in this scope
             printf("%lld\n",ans);
                             ^
0_0_25921942_20005.cpp:65:1: error: expected '}' at end of input
 }
 ^