program p1002;
const
    MAXL=100000000;
var
    a:array[0..MAXL] of boolean;
    f:array[0..MAXL] of longint;
    ll,s,t,m,i,j,k:longint;

function min(x,y:longint):longint;
begin
    if x<=y then min:=x
    else min:=y;
end;

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


begin
    readln(ll);
    readln(s,t,m);
    
    fillchar(a,sizeof(a),false);
    for i:=1 to m do begin
        read(k);
        a[k]:=true;
    end;
    
    if a[0] then f[0]:=1
    else f[0]:=0;
    
    for j:=0 to ll do begin
        for k:=s to min(t,ll-j) do begin
            i:=j+k;
            if a[i] then
                f[i]:=max(f[i],f[j]+1)
            else
                f[i]:=max(f[i],f[j]);
        end;
    end;
    
    writeln(f[ll]);
end.