books.cpp: In function 'void solve(int, int, ll, int)':
books.cpp:17:21: error: expected initializer before 'base'
17 | unsigned ll base = 0;
| ^~~~
books.cpp:18:37: error: 'base' was not declared in this scope
18 | for (int i = 1; i < K; ++i) base += Skim(i);
| ^~~~
books.cpp:23:26: error: 'base' was not declared in this scope
23 | (A * 2 < base + Skim(mid) ? R : L) = mid;
| ^~~~
books.cpp:28:21: error: 'base' was not declared in this scope
28 | if (A * 2 < base + Skim(L)) impossible();
| ^~~~
books.cpp:29:18: error: 'base' was not declared in this scope
29 | if (A <= base + skim(L)) {
| ^~~~
books.cpp:35:9: error: 'base' was not declared in this scope
35 | base += Skim(K);
| ^~~~