import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);

		long a = in.nextLong();
		long b = in.nextLong();
		long c = in.nextLong();
		long d = in.nextLong();

		System.out.println(countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d));

		in.close();
	}

	// 1以上limit以下の範囲でｃ、ｄの倍数でないものの個数を返す
	private static long countNonMultiple(long limit, long c, long d) {

		// cの倍数の個数
		long m_c = limit / c;

		// dの倍数の個数
		long m_d = limit / d;

		// c, dの最大公約数
		long gcd = getGCD(c, d);

		// c,dの最小公倍数
		long lcm = c * d / gcd;

		// lcm の個数
		long m_lcm = limit / lcm;

		return limit - m_c - m_d + m_lcm;
	}

	// 最大公約数を求める
	private static long getGCD(long c, long d) {
		if ( c % d == 0 ) return d;
		else return getGCD(d, c % d);
	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);

		long a = in.nextLong();
		long b = in.nextLong();
		long c = in.nextLong();
		long d = in.nextLong();

		System.out.println(countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d));

		in.close();
	}

	// 1以上limit以下の範囲でｃ、ｄの倍数でないものの個数を返す
	private static long countNonMultiple(long limit, long c, long d) {

		// cの倍数の個数
		long m_c = limit / c;

		// dの倍数の個数
		long m_d = limit / d;

		// c, dの最大公約数
		long gcd = getGCD(c, d);

		// c,dの最小公倍数
		long lcm = c * d / gcd;

		// lcm の個数
		long m_lcm = limit / lcm;

		return limit - m_c - m_d + m_lcm;
	}

	// 最大公約数を求める
	private static long getGCD(long c, long d) {
		if ( c % d == 0 ) return d;
		else return getGCD(d, c % d);
	}
} Main public static void main(String[] args) {
		Scanner in = new Scanner(System.in);

		long a = in.nextLong();
		long b = in.nextLong();
		long c = in.nextLong();
		long d = in.nextLong();

		System.out.println(countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d));

		in.close();
	} main {
		Scanner in = new Scanner(System.in);

		long a = in.nextLong();
		long b = in.nextLong();
		long c = in.nextLong();
		long d = in.nextLong();

		System.out.println(countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d));

		in.close();
	} Scanner in = new Scanner(System.in); in new Scanner(System.in) long a = in.nextLong(); a in.nextLong() in.nextLong in long b = in.nextLong(); b in.nextLong() in.nextLong in long c = in.nextLong(); c in.nextLong() in.nextLong in long d = in.nextLong(); d in.nextLong() in.nextLong in System.out.println(countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d)) System.out.println System.out System System.out countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d) countNonMultiple(b, c, d) countNonMultiple b c d countNonMultiple(a - 1, c, d) countNonMultiple a - 1 a 1 c d in.close() in.close in String[] args args // 1以上limit以下の範囲でｃ、ｄの倍数でないものの個数を返す
	private static long countNonMultiple(long limit, long c, long d) {

		// cの倍数の個数
		long m_c = limit / c;

		// dの倍数の個数
		long m_d = limit / d;

		// c, dの最大公約数
		long gcd = getGCD(c, d);

		// c,dの最小公倍数
		long lcm = c * d / gcd;

		// lcm の個数
		long m_lcm = limit / lcm;

		return limit - m_c - m_d + m_lcm;
	} countNonMultiple {

		// cの倍数の個数
		long m_c = limit / c;

		// dの倍数の個数
		long m_d = limit / d;

		// c, dの最大公約数
		long gcd = getGCD(c, d);

		// c,dの最小公倍数
		long lcm = c * d / gcd;

		// lcm の個数
		long m_lcm = limit / lcm;

		return limit - m_c - m_d + m_lcm;
	} long m_c = limit / c; m_c limit / c limit c long m_d = limit / d; m_d limit / d limit d long gcd = getGCD(c, d); gcd getGCD(c, d) getGCD c d long lcm = c * d / gcd; lcm c * d / gcd c * d c d gcd long m_lcm = limit / lcm; m_lcm limit / lcm limit lcm return limit - m_c - m_d + m_lcm; limit - m_c - m_d + m_lcm limit - m_c - m_d limit - m_c - m_d limit m_c m_d m_lcm long limit limit long c c long d d // 最大公約数を求める
	private static long getGCD(long c, long d) {
		if ( c % d == 0 ) return d;
		else return getGCD(d, c % d);
	} getGCD {
		if ( c % d == 0 ) return d;
		else return getGCD(d, c % d);
	} if ( c % d == 0 ) return d;
		else return getGCD(d, c % d); c % d == 0 c % d c d 0 return d; d return getGCD(d, c % d); getGCD(d, c % d) getGCD d c % d c d long c c long d d public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);

		long a = in.nextLong();
		long b = in.nextLong();
		long c = in.nextLong();
		long d = in.nextLong();

		System.out.println(countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d));

		in.close();
	}

	// 1以上limit以下の範囲でｃ、ｄの倍数でないものの個数を返す
	private static long countNonMultiple(long limit, long c, long d) {

		// cの倍数の個数
		long m_c = limit / c;

		// dの倍数の個数
		long m_d = limit / d;

		// c, dの最大公約数
		long gcd = getGCD(c, d);

		// c,dの最小公倍数
		long lcm = c * d / gcd;

		// lcm の個数
		long m_lcm = limit / lcm;

		return limit - m_c - m_d + m_lcm;
	}

	// 最大公約数を求める
	private static long getGCD(long c, long d) {
		if ( c % d == 0 ) return d;
		else return getGCD(d, c % d);
	}
} public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);

		long a = in.nextLong();
		long b = in.nextLong();
		long c = in.nextLong();
		long d = in.nextLong();

		System.out.println(countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d));

		in.close();
	}

	// 1以上limit以下の範囲でｃ、ｄの倍数でないものの個数を返す
	private static long countNonMultiple(long limit, long c, long d) {

		// cの倍数の個数
		long m_c = limit / c;

		// dの倍数の個数
		long m_d = limit / d;

		// c, dの最大公約数
		long gcd = getGCD(c, d);

		// c,dの最小公倍数
		long lcm = c * d / gcd;

		// lcm の個数
		long m_lcm = limit / lcm;

		return limit - m_c - m_d + m_lcm;
	}

	// 最大公約数を求める
	private static long getGCD(long c, long d) {
		if ( c % d == 0 ) return d;
		else return getGCD(d, c % d);
	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);

		long a = in.nextLong();
		long b = in.nextLong();
		long c = in.nextLong();
		long d = in.nextLong();

		System.out.println(countNonMultiple(b, c, d) - countNonMultiple(a - 1, c, d));

		in.close();
	}

	// 1以上limit以下の範囲でｃ、ｄの倍数でないものの個数を返す
	private static long countNonMultiple(long limit, long c, long d) {

		// cの倍数の個数
		long m_c = limit / c;

		// dの倍数の個数
		long m_d = limit / d;

		// c, dの最大公約数
		long gcd = getGCD(c, d);

		// c,dの最小公倍数
		long lcm = c * d / gcd;

		// lcm の個数
		long m_lcm = limit / lcm;

		return limit - m_c - m_d + m_lcm;
	}

	// 最大公約数を求める
	private static long getGCD(long c, long d) {
		if ( c % d == 0 ) return d;
		else return getGCD(d, c % d);
	}
}
