/in/foo.cc: In function 'int dfs(int, int, int, int)':
/in/foo.cc:69:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:72:13: warning: unused variable 'T' [-Wunused-variable]
         int T;
             ^