#include <stdio.h>
main()
{
    int a , b , c, d, count= 0;
    scanf("%d %d %d %d",&a,&b,&c,&d);
while (count == 0)
{
    if (c-b==0)
    {
        printf("Yes");
        break;
    }
    else if ((c-b)!=0)
        {c = c-b;}
    if ((d-a)==0)
    {
        printf("No");
        break;
    }
    else if ((d-a)!=0)
    {
        d = d-a;
    }
}
}