View Compilation Error

0_0_39901025_32315.cpp: In function 'void update(long long int, long long int, long long int, long long int, long long int)':
0_0_39901025_32315.cpp:29:27: error: 'sqrt' was not declared in this scope
   29 |                 tree[p] = sqrt(tree[p]);
      |                           ^~~~