View Compilation Error

0_0_38414809_9939.cpp: In function 'void solve()':
0_0_38414809_9939.cpp:102:9: error: 'string_view' was not declared in this scope
         string_view sv(s);
         ^
0_0_38414809_9939.cpp:103:17: error: 'sv' was not declared in this scope
         cout << sv.substr(1) << endl;
                 ^