4-​Thia-​1-​azabicyclo[3.2.0]​heptane-​2-​carboxylic acid, 6-​[[[[[6-​[[[[(4-​ethyl-​2,​3-​dioxo-​1-​piperazinyl)​carbonyl]​amino]​phenylacetyl]​amino]​-​3,​3-​dimethyl-​7-​oxo-​4-​thia-​1-​azabicyclo[3.2.0]​hept-​2-​yl]​carbonyl]​amino]​phenylacetyl]​ami