View Compilation Error

0_0_20750366_24306.cpp: In function 'int main()':
0_0_20750366_24306.cpp:12:7: error: 'cout' was not declared in this scope
       cout << "NO\n";
       ^
0_0_20750366_24306.cpp:14:5: error: 'cout' was not declared in this scope
     cout << a << endl;
     ^
0_0_20750366_24306.cpp:14:18: error: 'endl' was not declared in this scope
     cout << a << endl;
                  ^