View Compilation Error

0_0_35626789_14090.cpp: In function 'int main()':
0_0_35626789_14090.cpp:10:13: error: 'cin' was not declared in this scope
             cin>>a[i];
             ^
0_0_35626789_14090.cpp:22:13: error: 'cout' was not declared in this scope
             cout<<ans<<endl;
             ^
0_0_35626789_14090.cpp:22:24: error: 'endl' was not declared in this scope
             cout<<ans<<endl;
                        ^
0_0_35626789_14090.cpp:24:13: error: 'cout' was not declared in this scope
             cout<<"impossible"<<endl;
             ^
0_0_35626789_14090.cpp:24:33: error: 'endl' was not declared in this scope
             cout<<"impossible"<<endl;
                                 ^