(2S,2'S)-2,2'-[[(2R,5R)-1-[3,5-Difluoro-4-[4-(4-fluorophenyl)-1-piperidinyl]phenyl]-2,5-pyrrolidinediyl]bis(6-fluoro-1H-benzimidazole-5,2-diyl)]bis-1-pyrrolidinecarboxylic acid 1,1'-bis(1,1-dimethylethyl) ester