View Compilation Error

0_0_36422706_10371.cpp: In function 'int main()':
0_0_36422706_10371.cpp:7:18: error: 'read' was not declared in this scope
     int n = read();
                  ^
0_0_36422706_10371.cpp:13:15: error: 'ww' was not declared in this scope
             a[ww] = 1;
               ^
0_0_36422706_10371.cpp:21:19: error: 'ww' was not declared in this scope
             if (a[ww] == 1) f = 1;
                   ^
0_0_36422706_10371.cpp:22:15: error: 'ww' was not declared in this scope
             a[ww] = 1;
               ^