({[(3S,6aR)-2,2-dimethyl-1,1,5-trioxo-3,5,6,6a-tetrahydro-2H-1λ6-azeto[2,1-b][1,3]thiazol-3-yl]carbonyl}oxy)methyl (3S,6aR,6R)-6-{[(2R)-2-({[(3S,6aR,6R)-6-{[(2R)-2-amino-2-phenylacetyl]amino}-2,2-dimethyl-5-oxo-3,5,6,6a-tetrahydro-2H-azeto[2,1-b][1,3]thiazol-3-yl]carbonyl}amino)-2-phenylacetyl]amino}-2,2-dimethyl-5-oxo-3,5,6,6a-tetrahydro-2H-azeto[2,1-b][1,3]thiazole-3-carboxylate 4-methylbenzenesulfonic acid