answer.code: In member function ‘void Tree::build(int, int, int)’:
answer.code:214:16: error: ‘gcd’ was not declared in this scope
  214 |         t[v] = gcd(t[v << 1], t[v << 1 | 1]);
      |                ^~~
answer.code: In member function ‘int Tree::get(int, int, int, int, int)’:
answer.code:223:16: error: ‘gcd’ was not declared in this scope
  223 |         return gcd(get(v << 1, tl, tm, l, r), get(v << 1 | 1, tm + 1, tr, l, r));
      |                ^~~
answer.code: In function ‘void solve()’:
answer.code:245:21: error: ‘gcd’ was not declared in this scope
  245 |             qx[i] = gcd(qr[i] - ql[i] + 1, GCD.get(1, 0, m - 1, l, r));
      |                     ^~~