var f1,f2:text;
    ok:boolean;
    i,n,gs,s,st,r,br,pu,l,ic,cnt,j,g:longint;
    t:array[0..10000] of longint;
begin
        assign(f1,'koba.in');
        reset(f1);
        assign(f2,'koba.out');
        rewrite(f2);
        read(f1,n,t[1],t[2],t[3]);
        for i:=1 to 3 do
                t[i]:=t[i] mod 10;
        br:=0;
        for i:=4 to n do
        begin
                t[i]:=(t[i-1]+t[i-2]*t[i-3]) mod 10;;
                for j:=3 to i-1 do
                begin
                        ok:=true;
                        for g:=0 to 2 do
                                if t[i-g]<>t[j-g] then
                                        ok:=false;
                        if ok=true then
                        begin
                                gs:=j-2;
                                pu:=i-3;
                                br:=1;
                                break;
                        end;
                end;
                if br=1 then
                        break;
        end;
        if (gs=0)and(br=0) then
                gs:=n+1;
        for i:=1 to gs-1 do
                st:=st+t[i];
        for i:=gs to pu do
                s:=s+t[i];
        r:=n-gs+1;
        l:=pu-gs+1;
        cnt:=r div l;
        st:=st+s*cnt;
        ic:=r mod l;
        for i:=gs to gs+ic-1 do
                st:=st+t[i];
        writeln(f2,st);
        close(f1);
        close(f2);
end.