var
  n,a,ans,now,i,b,p:longint;

function jc(x:longint):longint;
var
  i,s:longint;
begin
  s:=1;
  for i:=1 to x do s:=s*i;
  jc:=s;
end;

begin
  assign(input,'sumcount.in'); reset(input);
  assign(output,'sumcount.out'); rewrite(output);
  readln(n,a,b,p);
  ans:=0;
  for i:=a to b do
  begin
    now:=jc(i+n-1) div (jc(i)*jc(n-1));
    ans:=(ans+now) mod p;
  end;
  writeln(ans);
  close(input);
  close(output);
end.