strange_device.cpp: In function 'int main()':
strange_device.cpp:13:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j=t;j<=l;j++)
                     ~^~~
strange_device.cpp:8:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%llu%llu%llu",&n,&a,&b);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.cpp:12:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%llu%llu",&t,&l);
         ~~~~~^~~~~~~~~~~~~~~~~~