/in/foo.cc: In function 'void dfs(ll, ll, ll)':
/in/foo.cc:59:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17' [-Wc++17-extensions]
   59 |     for(auto [v, nw] : adj[u]) {
      |              ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:93:20: warning: unused variable 'u' [-Wunused-variable]
   93 |     for(int i = 1, u, v, w; i <= m; i++) {
      |                    ^
/in/foo.cc:93:23: warning: unused variable 'v' [-Wunused-variable]
   93 |     for(int i = 1, u, v, w; i <= m; i++) {
      |                       ^
/in/foo.cc:93:26: warning: unused variable 'w' [-Wunused-variable]
   93 |     for(int i = 1, u, v, w; i <= m; i++) {
      |                          ^

FileNotFoundError('input/ex_tree2.in')