answer.code: In function ‘long long int LCA(long long int, long long int)’:
answer.code:55:12: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
   55 |         re(i,20,0)
      |            ^
answer.code:22:30: note: in definition of macro ‘re’
   22 | #define re(a,b,c) for(reg ll a=b;a>=c;--a)
      |                              ^
answer.code:62:12: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
   62 |         re(i,20,0)
      |            ^
answer.code:22:30: note: in definition of macro ‘re’
   22 | #define re(a,b,c) for(reg ll a=b;a>=c;--a)
      |                              ^
answer.code: In function ‘void dfs(long long int, long long int)’:
answer.code:81:12: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
   81 |         fo(i,1,20) f[u][i]=f[f[u][i-1]][i-1];
      |            ^
answer.code:21:30: note: in definition of macro ‘fo’
   21 | #define fo(a,b,c) for(reg ll a=b;a<=c;++a)
      |                              ^
answer.code: In function ‘void sol()’:
answer.code:163:12: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
  163 |         fo(i,1,n*2)
      |            ^
answer.code:21:30: note: in definition of macro ‘fo’
   21 | #define fo(a,b,c) for(reg ll a=b;a<=c;++a)
      |                              ^
answer.code:171:12: warning: ISO C++17 does not allow ‘register’ storage class specifier [-Wregister]
  171 |         fo(i,1,q)
      |            ^
answer.code:21:30: note: in definition of macro ‘fo’
   21 | #define fo(a,b,c) for(reg ll a=b;a<=c;++a)
      |                              ^
answer.code:183:47: error: ‘assert’ was not declared in this scope
  183 |                                 if(bel[y]!=x) assert(0);
      |                                               ^~~~~~
answer.code:18:1: note: ‘assert’ is defined in header ‘<cassert>’; did you forget to ‘#include <cassert>’?
   17 | #include <unordered_map>
  +++ |+#include <cassert>
   18 | #define ll long long