View Compilation Error

0_0_39469335_19447.cpp: In function 'int gcd(LL, LL)':
0_0_39469335_19447.cpp:14:20: error: '_gcd' was not declared in this scope; did you mean 'gcd'?
   14 |         return b ? _gcd(b, a%b) : a;
      |                    ^~~~
      |                    gcd