program koba;
{$APPTYPE CONSOLE}
uses
  SysUtils;

var i,j,n,m:integer;
    rez,t1,t2,t3,t4,a1,a2,a3,a4:Int64;
    fin,fout:text;
{*----------------------------------*}
begin
        assign(fin,'koba.in'); reset(fin);
        assign(fout,'koba.out'); rewrite(fout);

        read(fin,n,t1,t2,t3);
        T1:=T1 mod 10; T2:=T2 mod 10; T3:=T3 mod 10;

        for i:=1 to n do
        begin
                t4:=t3+t2*t1;
                t4:=t4 mod 10;

                a1:=t2;
                a2:=t3;
                a3:=t4;
                t3:=a3;
                t2:=a2;
                t1:=a1;

                rez:=rez+t4;

        end;

        Writeln(fout,rez);

        close(fin);
        close(fout);
end.