foo.cpp: In function 'void bfs()':
foo.cpp:70:22: warning: unknown conversion type character 'l' in format [-Wformat=]
  printf("%lld\n", ans);
                      ^
foo.cpp:70:22: warning: too many arguments for format [-Wformat-extra-args]
foo.cpp:70:22: warning: unknown conversion type character 'l' in format [-Wformat=]
foo.cpp:70:22: warning: too many arguments for format [-Wformat-extra-args]