N-acetyl-3-(2-naphthyl)-D-alanyl-p-chloro-D-phenylalanyl-3-(3-pyridyl)-D-alanyl-L-seryl-L-tyrosyl-N(sup 6)-(N,N'-diethylamidino)-D-lysyl-L-leucyl-N(sup 6)-(N,N'-diethylamidino)-L-lysyl-L-prolyl-D-alaninamide diacetate (salt)