program-id.y.data division.working-storage section.
1 i pic 9.
1 s pic x(19).
1 t pic x(19).
procedure division.a.accept s accept t move 1 to i.b.if
s(1:3)<>s(1+i*4:3)or t(1:3)<>t(1+i*4:3)add 1 to i go b.if
s<>t display i" "s(1:3)t(1:3)go a.