import java.io.OutputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.InputMismatchException; import java.io.IOException; import java.io.InputStream; /** * Built using CHelper plug-in * Actual solution is at the top * * @author Pradyumn Agrawal coderbond007 PLEASE!! PLEASE!! HACK MY SOLUTION!! */ public class Solution { public static void main(String[] args) { InputStream inputStream = System.in; OutputStream outputStream = System.out; FastReader in = new FastReader(inputStream); PrintWriter out = new PrintWriter(outputStream); HalloweenSale solver = new HalloweenSale(); solver.solve(1, in, out); out.close(); } static class HalloweenSale { public void solve(int testNumber, FastReader in, PrintWriter out) { int p = in.nextInt(); int d = in.nextInt(); int m = in.nextInt(); int s = in.nextInt(); int ct = 0; while (p >= m) { s -= p; if (s >= 0) ct += 1; else break; p -= d; p = Math.max(p, m); } out.println(ct); } } static class FastReader { private InputStream stream; private byte[] buf = new byte[8192]; private int curChar; private int pnumChars; private FastReader.SpaceCharFilter filter; public FastReader(InputStream stream) { this.stream = stream; } private int pread() { if (pnumChars == -1) { throw new InputMismatchException(); } if (curChar >= pnumChars) { curChar = 0; try { pnumChars = stream.read(buf); } catch (IOException e) { throw new InputMismatchException(); } if (pnumChars <= 0) { return -1; } } return buf[curChar++]; } public int nextInt() { int c = pread(); while (isSpaceChar(c)) c = pread(); int sgn = 1; if (c == '-') { sgn = -1; c = pread(); } int res = 0; do { if (c == ',') { c = pread(); } if (c < '0' || c > '9') { throw new InputMismatchException(); } res *= 10; res += c - '0'; c = pread(); } while (!isSpaceChar(c)); return res * sgn; } private boolean isSpaceChar(int c) { if (filter != null) { return filter.isSpaceChar(c); } return isWhitespace(c); } private static boolean isWhitespace(int c) { return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1; } private interface SpaceCharFilter { public boolean isSpaceChar(int ch); } } }