View Compilation Error

0_0_36392930_29972.cpp: In function 'int main()':
0_0_36392930_29972.cpp:19:34: error: expression cannot be used as a function
             for (int i = j.first(); i <= j.second(); i++)
                                  ^
0_0_36392930_29972.cpp:19:51: error: expression cannot be used as a function
             for (int i = j.first(); i <= j.second(); i++)
                                                   ^