import std.stdio, std.string, std.conv, std.algorithm;
import std.range, std.array, std.math, std.typecons, std.functional;

void main() {
    long h, w, n, k;
    scan(h, w, n, k);

    if (k == n) k = 0;

    if ((h * w) % n == k) {
        writeln("YES");
    }
    else {
        writeln("NO");
    }
}

void scan(T...)(ref T args) {
    auto line = readln.split;
    foreach (ref arg ; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}