xaucon_dainhat

uses crt;

var     s1,s2,kq:string;
        a:array[0..1000,0..1000] of longint;
        i,j:longint;

function max(x,y:longint):longint;
begin
        if x>y then exit(x) else exit(y);
end;

begin
        clrscr;
        readln(s1); readln(s2);
        kq:='';
        {nap cong thuc}
        for i:=0 to length(s1) do a[i,j]:=0;
        for i:=1 to length(s1) do
                 for j:=1 to length(s2) do
                 if s1[i]=s2[j] then a[i,j]:=a[i-1,j-1]+1 else a[i,j]:=max(a[i-1,j],a[i,j-1]);
        {truy vet}
        i:=length(s1); j:=length(s2);
        While (i>0) and (j>0) do
                if s1[i]=s2[j] then
                        begin
                        kq:=s1[i]+kq;
                        dec(i); dec(j);
                        end
                else if a[i-1,j]=a[i,j] then dec(i) else dec(j);
        write(kq);
readln
end.