foo.cc: In function 'int main()':
foo.cc:22:13: warning: unused variable 'l' [-Wunused-variable]
     int n,i,l,r,m,x,y;
             ^
foo.cc:22:15: warning: unused variable 'r' [-Wunused-variable]
     int n,i,l,r,m,x,y;
               ^
foo.cc:22:17: warning: unused variable 'm' [-Wunused-variable]
     int n,i,l,r,m,x,y;
                 ^

[Hydro](https://hydro.ac)提供评测服务