class A:
def foo(self):
print("foo")
def __del__(self):
print("del")
for i in range(10):
a = A()
a.foo();
b = A()
a.link=b
b.link=a
Y2xhc3MgQToKICAgIGRlZiBmb28oc2VsZik6CiAgICAgICAgcHJpbnQoImZvbyIpCgogICAgZGVmIF9fZGVsX18oc2VsZik6CiAgICAgICAgcHJpbnQoImRlbCIpCgpmb3IgaSBpbiByYW5nZSgxMCk6CiAgICBhID0gQSgpCiAgICBhLmZvbygpOwogICAgYiA9IEEoKQogICAgYS5saW5rPWIKICAgIGIubGluaz1hCg==