View Compilation Error

0_0_39567444_18588.cpp: In function 'int findCycleLength(std::vector<int>&)':
0_0_39567444_18588.cpp:20:55: error: '__gcd' was not declared in this scope
   20 |             cycleLength = (cycleLength * cycleSize) / __gcd(cycleLength, cycleSize);
      |                                                       ^~~~~