How can I delete the cells in Col B if their left 16 characters do not
match the cells in Col A?

a b
000000006-6 1967 000000002-2 1957 0017731
000000006-6 1968 000000002-2 2002 0235432
000000012-1 1996 000000003-3 1957 0017043
000000034-1 1991 000000003-3 2002 0235433
000000048-4 1994 000000003-3 2003 0254130
000000048-4 1995 000000004-4 2002 0235434
000000048-4 1996 000000005-5 2002 0235435
000000048-4 1997 000000005-5 2003 0254131
000000059-4 1982 000000006-6 1967 0008339
000000059-4 1983 000000006-6 1968 0006437
000000059-4 1984 000000006-6 2002 0235436
000000059-4 1990 000000008-8 1963 0017131
000000059-4 1991 000000010-9 2002 0235437
000000063-7 1993 000000012-1 1996 0149047
000000063-7 1995 000000014-3 2002 0235438
000000063-7 1996 000000015-4 2002 0235439
000000063-7 1997 000000016-5 2002 0235440
000000034-1 1991 0101141
000000040-6 1961 0003885
000000043-9 1978 0034376
000000048-4 1994 0122266
000000048-4 1995 0135082
000000048-4 1996 0149048
000000048-4 1997 0161502
000000048-4 1998 0175210
000000048-4 1999 0186927
000000048-4 2000 0197851
000000048-4 2002 0235441
000000048-4 2008 0355864
000000048-4 2009 0372791
000000048-4 2010 0385805
000000048-4 2011 0398314
000000049-5 1959 0017982
000000051-6 1958 0016884
000000059-4 1982 0049201
000000059-4 1983 0054814
000000059-4 1984 0059644
000000059-4 1990 0094340
000000059-4 1991 0102782
000000061-5 1962 0017524
000000063-7 1993 0114767
000000063-7 1995 0135083