View Compilation Error

0_0_20627277_7500.cpp: In function 'int main()':
0_0_20627277_7500.cpp:37:12: error: 'cin' was not declared in this scope
     while (cin>>n>>m)
            ^
0_0_20627277_7500.cpp:69:9: error: 'cout' was not declared in this scope
         cout<<ans<<endl;
         ^
0_0_20627277_7500.cpp:69:20: error: 'endl' was not declared in this scope
         cout<<ans<<endl;
                    ^