View Compilation Error

0_0_29048779_15592.cpp: In function 'int main()':
0_0_29048779_15592.cpp:27:13: error: 'l' was not declared in this scope
  while(cin>>l>>r)
             ^
0_0_29048779_15592.cpp:27:16: error: 'r' was not declared in this scope
  while(cin>>l>>r)
                ^