import java.math.BigInteger;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		new Main().run();
	}

	public void run() {
		Scanner sc = new Scanner(System.in);
		long t = sc.nextLong();
		long a = sc.nextLong();
		long b = sc.nextLong();
		if (!(1 <= t && 1 <= a && 1 <= b && t <= 1e18 && a <= 1e18 && b <= 1e18))
			throw new AssertionError();

		BigInteger T = BigInteger.valueOf(t).subtract(BigInteger.ONE);
		BigInteger A = BigInteger.valueOf(a);
		BigInteger B = BigInteger.valueOf(b);

		BigInteger ans = BigInteger.ZERO;
		ans = ans.add(T.divide(A));
		ans = ans.add(T.divide(B));
		ans = ans.subtract(T.divide(A.multiply(B).divide(A.gcd(B))));
		ans = ans.add(BigInteger.ONE);
		System.out.println(ans);
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}
}