include <stdio.h>

int main() {

long long a, b, c, d;
if (scanf("%lld %lld %lld %lld", &a, &b, &c, &d) == 4) {
    long long max = a;
    if (b > max) max = b;
    if (c > max) max = c;

    long long min = a;
    if (b < min) min = b;
    if (c < min) min = c;

    if (max - min <= d) {
        printf("Yes\n");
    } else {
        printf("No\n");
    }
}
return 0;

}