View Compilation Error

0_0_33571787_30672.cpp: In function 'void update(int, int, int, int, int)':
0_0_33571787_30672.cpp:25:21: error: 'po' was not declared in this scope
   if (l ==r && l == po
                     ^
0_0_33571787_30672.cpp:25:21: error: expected ')' at end of input
0_0_33571787_30672.cpp:25:21: error: expected statement at end of input
0_0_33571787_30672.cpp:25:21: error: expected '}' at end of input