View Compilation Error

0_0_39563227_21459.cpp: In function 'int fastInput()':
0_0_39563227_21459.cpp:13:18: error: 'getchar_unlocked' was not declared in this scope; did you mean '_getchar_nolock'?
   13 |     while ((ch = getchar_unlocked()) < '0' || ch > '9');
      |                  ^~~~~~~~~~~~~~~~
      |                  _getchar_nolock
0_0_39563227_21459.cpp:15:18: error: 'getchar_unlocked' was not declared in this scope; did you mean '_getchar_nolock'?
   15 |     while ((ch = getchar_unlocked()) >= '0' && ch <= '9') {
      |                  ^~~~~~~~~~~~~~~~
      |                  _getchar_nolock