import std.algorithm, std.array, std.container, std.range;
import std.numeric, std.math, std.bigint, std.bitmanip, std.random;
import std.string, std.conv, std.stdio, std.typecons;

void main()
{
  auto rd = readln.split.map!(to!long);
  auto h = rd[0], w = rd[1], n = rd[2], k = rd[3];

  auto r = h * w % n;
  if (k == n)
    writeln(r == 0 ? "YES" : "NO");
  else
    writeln(r == k ? "YES" : "NO");
}