Program Subsir;
uses crt;
type Matrix= array[1..1024,1..1024] of integer;
Vector= array[1..1024] of integer;
var D,B:Matrix;
T,S,C:Vector;
k,n,m,i,j,x,y,z:integer;
f1,f2:text;
Procedure Afisare(k,h:integer ) ;
begin
if B[k,h]=1 then begin Afisare(k-1,h-1); write(f2,T[k],' '); end
else
if B[k,h]=2 then Afisare(k-1,h)
else
if B[k,h]=3 then Afisare(k,h-1);
end;
begin
clrscr;
assign(f1,'cmlsc.in'); reset(f1);
assign(f2,'cmlsc.out'); rewrite(f2);
readln(f1,n,m);
for i:=0 to n+1 do
for j:=0 to m+1 do
D[i,j]:=0;
for i:=1 to n do
read(f1,T[i]);
for i:=1 to m do
read(f1,S[i]);
for i:=1 to n do
for j:=1 to m do
if T[i]=S[j] then begin D[i,j]:=D[i-1,j-1]+1; B[i,j]:=1; end
else
if D[i-1,j]>D[i,j-1] then
begin
D[i,j]:=D[i-1,j];
B[i,j]:=2;
end
else
begin
D[i,j]:=D[i,j-1];
B[i,j]:=3;
end;
z:=D[1,1];
for i:=1 to n do
for j:=1 to m do
if D[i,j]>=z then begin z:=D[i,j]; x:=i; y:=j; end;
writeln(f2,z);
Afisare(n,m);
close(f1); close(f2);
end.