View Compilation Error

0_0_22713513_15216.cpp: In function 'int main()':
0_0_22713513_15216.cpp:30:21: error: 'l' was not declared in this scope
 while(scanf("%d%d",&l,&r)==2 && l && r){
                     ^
0_0_22713513_15216.cpp:30:24: error: 'r' was not declared in this scope
 while(scanf("%d%d",&l,&r)==2 && l && r){
                        ^