#include <stdio.h>

int takahashi_attack(int hp, int at)
{
    int remain_hp;
    remain_hp = hp - at;
    return remain_hp;
}

int aoki_attack(int hp, int at)
{
    int remain_hp;
    remain_hp = hp - at;
    return remain_hp;
}

int main(void)
{
    int A, B, C, D;
    int aoki_remain;
    int takahashi_remain;

    scanf("%d %d %d %d", &A, &B, &C, &D);
    while (1)
    {
        aoki_remain = takahashi_attack(C, B);
        C = aoki_remain;
        printf("aoki_remain:%d\n", aoki_remain);
        if (aoki_remain == 0)
        {
            printf("Yes\n");
            break;
        }
        takahashi_remain = aoki_attack(A, D);
        A = takahashi_remain;
        printf("takahashi_remain:%d\n", takahashi_remain);
        if (takahashi_remain == 0)
        {
            printf("No\n");
            break;
        }
    }
    return 0;
}