import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int x1 = sc.nextInt();
		long y1 = sc.nextInt();
		int x2 = sc.nextInt();
		int y2 = sc.nextInt();
		int x3 = sc.nextInt();
		int y3 = sc.nextInt();
		long ans = 0;
		for (int i = 0; i < 1000000; i++) {
		    ans = y1 * i + x1;
		    if (ans % y2 == x2) {
		        break;
		    }
		}
		if (ans % y2 != x2) {
		    System.out.println(-1);
		    return;
		}
		long y1y2 = lcm(y1, y2);
		long fine = 0;
		for (int i = 0; i < 1000000; i++) {
		    fine = y1y2 * i + ans;
		    if (fine % y3 == x3) {
		        System.out.println(fine);
		        return;
		    }
		}
		System.out.println(-1);
   }
    static long lcm(long x, long y) {
        return x / gcd(x, y) * y;
    }
    
    static long gcd(long x, long y) {
        if (x % y == 0) {
            return y;
        } else {
            return gcd(y, x % y);
        }
    }
}