View Compilation Error

0_0_29577988_14096.cpp: In function 'int main()':
0_0_29577988_14096.cpp:18:8: error: 'cin' was not declared in this scope
  while(cin>>n>>k){
        ^
0_0_29577988_14096.cpp:32:3: error: 'cout' was not declared in this scope
   cout<<s[n][k]<<endl;
   ^
0_0_29577988_14096.cpp:32:18: error: 'endl' was not declared in this scope
   cout<<s[n][k]<<endl;
                  ^