View Compilation Error

0_0_23773915_31380.cpp: In function 'int main()':
0_0_23773915_31380.cpp:9:3: error: 'cout' was not declared in this scope
   cout<<a*b-a-b<<(a-1)*(b-1)/2<<endl;    
   ^
0_0_23773915_31380.cpp:9:3: note: suggested alternative:
In file included from 0_0_23773915_31380.cpp:1:0:
GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^
0_0_23773915_31380.cpp:9:33: error: 'endl' was not declared in this scope
   cout<<a*b-a-b<<(a-1)*(b-1)/2<<endl;    
                                 ^
0_0_23773915_31380.cpp:9:33: note: suggested alternative:
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:39:0,
                 from 0_0_23773915_31380.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/ostream:564:5: note:   'std::endl'
     endl(basic_ostream<_CharT, _Traits>& __os)
     ^