View Compilation Error

0_0_25320567_13614.cpp: In function 'int main()':
0_0_25320567_13614.cpp:9:8: error: 'cin' was not declared in this scope
  while(cin>>s1) {
        ^
0_0_25320567_13614.cpp:53:3: error: 'cout' was not declared in this scope
   cout<<ans<<endl;
   ^
0_0_25320567_13614.cpp:53:14: error: 'endl' was not declared in this scope
   cout<<ans<<endl;
              ^