(1S,6aS,6R)-5-{[(3S,5S)-1-[(2S,3R)-2-[(2S,3R)-4-{[(3S,5S)-5-{[(3-carboxyphenyl)amino]carbonyl}pyrrolidin-3-yl]sulfanyl}-5-carboxy-3-methyl-2,3-dihydro-1H-pyrrol-2-yl]-3-hydroxy-1-oxobutyl]-5-{[(3-carboxyphenyl)amino]carbonyl}pyrrolidin-3-yl]sulfanyl}-1-[(1R)-1-hydroxyethyl]-6-methyl-2-oxo-1,2,6,6a-tetrahydroazeto[1,2-a]pyrrole-4-carboxylic acid (1S,6aS,6R)-5-{[(3S,5S)-1-[(2S,3R)-2-[(2S,3R)-4-{[(3S,5S)-5-{[(3-carboxyphenyl)amino]carbonyl}pyrrolidin-3-yl]sulfanyl}-5-carboxy-3-methyl-3,4-dihydro-2H-pyrrol-2-yl]-3-hydroxy-1-oxobutyl]-5-{[(3-carboxyphenyl)amino]carbonyl}pyrrolidin-3-yl]sulfanyl}-1-[(1R)-1-hydroxyethyl]-6-methyl-2-oxo-1,2,6,6a-tetrahydroazeto[1,2-a]pyrrole-4-carboxylic acid