View Compilation Error

0_0_16889071_13301.cpp: In function 'LL work()':
0_0_16889071_13301.cpp:49:31: error: unable to find numeric literal operator 'operator""s'
                 d = btnl(i) - 1s;
                               ^
0_0_16889071_13301.cpp:49:31: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes