Vasya's telephone contains n photos. Photo number 1 is currently opened on the phone. It is allowed to move left and right to the adjacent photo by swiping finger over the screen. If you swipe left from the first photo, you reach photo n. Similarly, by swiping right from the last photo you reach photo 1. It takes a seconds to swipe from photo to adjacent.

For each photo it is known which orientation is intended for it — horizontal or vertical. Phone is in the vertical orientation and can't be rotated. It takes b second to change orientation of the photo.

Vasya has T seconds to watch photos. He want to watch as many photos as possible. If Vasya opens the photo for the first time, he spends 1 second to notice all details in it. If photo is in the wrong orientation, he spends b seconds on rotating it before watching it. If Vasya has already opened the photo, he just skips it (so he doesn't spend any time for watching it or for changing its orientation). It is not allowed to skip unseen photos.

Help Vasya find the maximum number of photos he is able to watch during T seconds.

Input

The first line of the input contains 4 integers n, a, b, T (1 ≤ n ≤ 5·105, 1 ≤ a, b ≤ 1000, 1 ≤ T ≤ 109) — the number of photos, time to move from a photo to adjacent, time to change orientation of a photo and time Vasya can spend for watching photo.

Second line of the input contains a string of length n containing symbols 'w' and 'h'. 

If the i-th position of a string contains 'w', then the photo i should be seen in the horizontal orientation.

If the i-th position of a string contains 'h', then the photo i should be seen in vertical orientation.

Output

Output the only integer, the maximum number of photos Vasya is able to watch during those T seconds.

Examples

Input

4 2 3 10
wwhw


Output

2


Input

5 2 4 13
hhwhh


Output

4


Input

5 2 4 1000
hhwhh


Output

5


Input

3 1 100 10
whw


Output

0

Note

In the first sample test you can rotate the first photo (3 seconds), watch the first photo (1 seconds), move left (2 second), rotate fourth photo (3 seconds), watch fourth photo (1 second). The whole process takes exactly 10 seconds.

Note that in the last sample test the time is not enough even to watch the first photo, also you can't skip it.
import java.util.*;
import java.io.*;
import java.awt.Point;
import java.math.BigDecimal;
import java.math.BigInteger;

import static java.lang.Math.*;


public class B implements Runnable{
	
	final static Random rnd = new Random();
	
	// SOLUTION!!! 
	// HACK ME PLEASE IF YOU CAN!!!
	// PLEASE!!!
	// PLEASE!!!
	// PLEASE!!!
	void solve() {
		int n = readInt();
		
		int shiftTime = readInt();
		int rotateTime = readInt();
		long totalTime = readLong();
		
		char[] types = readCharArray();
		
		int answer = getAnswer(n, shiftTime, rotateTime, totalTime, types);
		out.println(answer);
	}
	
	static final char NEED_ROTATE = 'w';
	
	long getViewTime(char type, long rotateTime) {
		long time = 1;
		if (type == NEED_ROTATE) time += rotateTime;
		return time;
	}
	
	int getAnswer(int n, 
			long shiftTime, long rotateTime, long totalTime,
			char[] types) {
		int answer = 0;
		
		long firstTime = getViewTime(types[0], rotateTime);
		if (firstTime <= totalTime) {
			totalTime -= firstTime;
			
			long[] prefTimes = new long[n];
			for (int i = 1; i < n; ++i) {
				prefTimes[i] = prefTimes[i - 1] + shiftTime + getViewTime(types[i], rotateTime);
			}
			
			long[] suffTimes = new long[n + 1];
			for (int i = n - 1; i >= 0; --i) {
				suffTimes[i] = suffTimes[i + 1] + shiftTime + getViewTime(types[i], rotateTime);
			}
			
			// search suffix
			for (int i = n - 1, j = n - 1; i > 0; --i) {
				long suffTime = suffTimes[i];
				if (totalTime >= suffTime) {
					int count = n - i;
					
					long canSeePrefixTime = totalTime - suffTime - count * shiftTime;
					
					j = min(j, i - 1);
					while (j > 0 && prefTimes[j] > canSeePrefixTime) {
						--j;
					}
					
					if (j > 0 && prefTimes[j] <= canSeePrefixTime) {
						count += j;
					}
					
					answer = max(answer, count);
				}
			}
			
			// search prefix
			for (int i = 1, j = 1; i < n; ++i) {
				long prefTime = prefTimes[i];
				if (totalTime >= prefTime) {
					int count = i;
					
					long canSeeSuffixTime = totalTime - prefTime - count * shiftTime;
					j = max(j, i + 1);
					
					while (j < n && suffTimes[j] > canSeeSuffixTime) {
						++j;
					}
					
					if (j < n && suffTimes[j] <= canSeeSuffixTime) {
						count += (n - j);
					}
					
					answer = max(answer, count);
				}
			}
			
			++answer; // we inc, because we saw first photo
		}
		
		return answer;
	}
	
	/////////////////////////////////////////////////////////////////////

	final boolean FIRST_INPUT_STRING = false;
	final boolean ONLINE_JUDGE = System.getProperty("ONLINE_JUDGE") != null;
	
	final static int MAX_STACK_SIZE = 128;
	
	/////////////////////////////////////////////////////////////////////
	
	public void run(){
		try{
			timeBegin = System.currentTimeMillis();
			Locale.setDefault(Locale.US);
			
			init();
			
			if (ONLINE_JUDGE) {
				solve();
			} else {
				while (true) {
					try {
						solve();
					} catch (NumberFormatException e) {
						break;
					} catch (NullPointerException e) {
						if (FIRST_INPUT_STRING) break;
						else throw e;
					}
				}
			}
			
			out.close();
			time();
		}catch (Exception e){
			e.printStackTrace(System.err);
			System.exit(-1);
		}
	}
	
	/////////////////////////////////////////////////////////////////////
	
	BufferedReader in;
	OutputWriter out;
	StringTokenizer tok = new StringTokenizer("");
	
	public static void main(String[] args){
		new Thread(null, new B(), "", MAX_STACK_SIZE * (1L << 20)).start();
	}
	
	/////////////////////////////////////////////////////////////////////
	
	void init() throws FileNotFoundException{
		Locale.setDefault(Locale.US);
		
		if (ONLINE_JUDGE){
			in = new BufferedReader(new InputStreamReader(System.in));
			out = new OutputWriter(System.out);
		}else{
			in = new BufferedReader(new FileReader("input.txt"));
			out = new OutputWriter("output.txt");
		}
	}
	
	////////////////////////////////////////////////////////////////
	
	long timeBegin, timeEnd;

	void time(){
		timeEnd = System.currentTimeMillis();
		System.err.println("Time = " + (timeEnd - timeBegin));
	}
	
	void debug(Object... objects){
		if (ONLINE_JUDGE){
			for (Object o: objects){
				System.err.println(o.toString());
			}
		}
	}
	
	/////////////////////////////////////////////////////////////////////
	
	String delim = " ";
	
	String readLine() {
		try {
			return in.readLine();
		} catch (IOException e) {
			throw new RuntimeIOException(e);
		}
	}
	
	String readString() {
		try {
			while(!tok.hasMoreTokens()){
				tok = new StringTokenizer(readLine());
			}
			
			return tok.nextToken(delim);
		} catch (NullPointerException e) {
			return null;
		}
	}
	
	/////////////////////////////////////////////////////////////////
	
	final char NOT_A_SYMBOL = '\0';
	
	char readChar() {
		try {
			int intValue = in.read();
			
			if (intValue == -1){
				return NOT_A_SYMBOL;
			}
			
			return (char) intValue;
		} catch (IOException e) {
			throw new RuntimeIOException(e);
		}
	}
	
	char[] readCharArray() {
		return readLine().toCharArray();
	}
	
	char[][] readCharField(int rowsCount) {
		char[][] field = new char[rowsCount][];
		for (int row = 0; row < rowsCount; ++row) {
			field[row] = readCharArray();
		}
		
		return field;
	}
	
	/////////////////////////////////////////////////////////////////
	
	int readInt() {
		return Integer.parseInt(readString());
	}
	
	int[] readIntArray(int size) {
		int[] array = new int[size];
		
		for (int index = 0; index < size; ++index){
			array[index] = readInt();
		}
		
		return array;
	}
	
	int[] readSortedIntArray(int size) {
		Integer[] array = new Integer[size];
		
		for (int index = 0; index < size; ++index) {
			array[index] = readInt();
		}
		Arrays.sort(array);
		
		int[] sortedArray = new int[size];
		for (int index = 0; index < size; ++index) {
			sortedArray[index] = array[index];
		}
		
		return sortedArray;
	}
	
	int[] readIntArrayWithDecrease(int size) {
		int[] array = readIntArray(size);
		
		for (int i = 0; i < size; ++i) {
			array[i]--;
		}
		
		return array;
	}
	
	///////////////////////////////////////////////////////////////////
	
	int[][] readIntMatrix(int rowsCount, int columnsCount) {
		int[][] matrix = new int[rowsCount][];
		
		for (int rowIndex = 0; rowIndex < rowsCount; ++rowIndex) {
			matrix[rowIndex] = readIntArray(columnsCount);
		}
		
		return matrix;
	}
	
	int[][] readIntMatrixWithDecrease(int rowsCount, int columnsCount) {
		int[][] matrix = new int[rowsCount][];
		
		for (int rowIndex = 0; rowIndex < rowsCount; ++rowIndex) {
			matrix[rowIndex] = readIntArrayWithDecrease(columnsCount);
		}
		
		return matrix;
	}
	
	///////////////////////////////////////////////////////////////////
	
	long readLong() {
		return Long.parseLong(readString());
	}
	
	long[] readLongArray(int size) {
		long[] array = new long[size];
		
		for (int index = 0; index < size; ++index){
			array[index] = readLong();
		}
		
		return array;
	}
	
	////////////////////////////////////////////////////////////////////
	
	double readDouble() {
		return Double.parseDouble(readString());
	}
	
	double[] readDoubleArray(int size) {
		double[] array = new double[size];
		
		for (int index = 0; index < size; ++index){
			array[index] = readDouble();
		}
		
		return array;
	}
	
	////////////////////////////////////////////////////////////////////
		
	BigInteger readBigInteger() {
		return new BigInteger(readString());
	}
	
	BigDecimal readBigDecimal() {
		return new BigDecimal(readString());
	}
	
	/////////////////////////////////////////////////////////////////////
	
	Point readPoint() {
		int x = readInt();
		int y = readInt();
		return new Point(x, y);
	}
	
	Point[] readPointArray(int size) {
		Point[] array = new Point[size];
		
		for (int index = 0; index < size; ++index){
			array[index] = readPoint();
		}
		
		return array;
	}
	
	/////////////////////////////////////////////////////////////////////
	
	List<Integer>[] readGraph(int vertexNumber, int edgeNumber) {
		@SuppressWarnings("unchecked")
		List<Integer>[] graph = new List[vertexNumber];
		
		for (int index = 0; index < vertexNumber; ++index){
			graph[index] = new ArrayList<Integer>();
		}
		
		while (edgeNumber-- > 0){
			int from = readInt() - 1;
			int to = readInt() - 1;
			
			graph[from].add(to);
			graph[to].add(from);
		}
		
		return graph;
	}
	
	/////////////////////////////////////////////////////////////////////
	
	static class IntIndexPair {
		
		static Comparator<IntIndexPair> increaseComparator = new Comparator<IntIndexPair>() {
			
			@Override
			public int compare(IntIndexPair indexPair1, IntIndexPair indexPair2) {
				int value1 = indexPair1.value;
				int value2 = indexPair2.value;
				
				if (value1 != value2) return value1 - value2;
				
				int index1 = indexPair1.index;
				int index2 = indexPair2.index;
				
				return index1 - index2;
			}
		};
		
		static Comparator<IntIndexPair> decreaseComparator = new Comparator<IntIndexPair>() {
			
			@Override
			public int compare(IntIndexPair indexPair1, IntIndexPair indexPair2) {
				int value1 = indexPair1.value;
				int value2 = indexPair2.value;
				
				if (value1 != value2) return -(value1 - value2);
				
				int index1 = indexPair1.index;
				int index2 = indexPair2.index;
				
				return index1 - index2;
			}
		};
		
		int value, index;

		public IntIndexPair(int value, int index) {
			super();
			this.value = value;
			this.index = index;
		}		
		
		public int getRealIndex() {
			return index + 1;
		}
	}
	
	IntIndexPair[] readIntIndexArray(int size) {
		IntIndexPair[] array = new IntIndexPair[size];
		
		for (int index = 0; index < size; ++index) {
			array[index] = new IntIndexPair(readInt(), index);
		}
		
		return array;
	}
	
	/////////////////////////////////////////////////////////////////////
	
	static class OutputWriter extends PrintWriter {

		final int DEFAULT_PRECISION = 12;
		
		protected int precision;
		protected String format, formatWithSpace;
		
		{
			precision = DEFAULT_PRECISION;
			
			format = createFormat(precision);
			formatWithSpace = format + " ";
		}
		
		public OutputWriter(OutputStream out) {
			super(out);
		}

		public OutputWriter(String fileName) throws FileNotFoundException {
			super(fileName);
		}
		
		public int getPrecision() {
			return precision;
		}

		public void setPrecision(int precision) {
			precision = max(0, precision);
			this.precision = precision;
			
			format = createFormat(precision);
			formatWithSpace = format + " ";
		}
		
		private String createFormat(int precision){
			return "%." + precision + "f";
		}
		
		@Override
		public void print(double d){
			printf(format, d);
		}
		
		public void printWithSpace(double d){
			printf(formatWithSpace, d);
		}

		public void printAll(double...d){
			for (int i = 0; i < d.length - 1; ++i){
				printWithSpace(d[i]);
			}
			
			print(d[d.length - 1]);
		}
		
		@Override
		public void println(double d){
			printlnAll(d);
		}
		
		public void printlnAll(double... d){
			printAll(d);
			println();
		}
	}
	
	/////////////////////////////////////////////////////////////////////
	
	static class RuntimeIOException extends RuntimeException {

		/**
		 * 
		 */
		private static final long serialVersionUID = -6463830523020118289L;

		public RuntimeIOException(Throwable cause) {
			super(cause);
		}
	}
	
	/////////////////////////////////////////////////////////////////////
	//////////////// Some useful constants and functions ////////////////
	/////////////////////////////////////////////////////////////////////
	
	static final int[][] steps = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}}; 
	static final int[][] steps8 = {
			{-1, 0}, {1, 0}, {0, -1}, {0, 1},
			{-1, -1}, {1, 1}, {1, -1}, {-1, 1}
	};
	
	static final boolean checkCell(int row, int rowsCount, int column, int columnsCount) {
		return checkIndex(row, rowsCount) && checkIndex(column, columnsCount);
	}
	
	static final boolean checkIndex(int index, int lim){
		return (0 <= index && index < lim);
	}
	
	/////////////////////////////////////////////////////////////////////
	
	static final boolean checkBit(int mask, int bit){
		return (mask & (1 << bit)) != 0;
	}
	
	static final boolean checkBit(long mask, int bit) {
		return (mask & (1L << bit)) != 0;
	}
	
	/////////////////////////////////////////////////////////////////////
	
	static final long getSum(int[] array) {
		long sum = 0;
		for (int value: array) {
			sum += value;
		}
		
		return sum;
	}
	
	static final Point getMinMax(int[] array) {
		int min = array[0];
		int max = array[0];
		
		for (int index = 0, size = array.length; index < size; ++index, ++index) {
			int value = array[index];
			
			if (index == size - 1) {
				min = min(min, value);
				max = max(max, value);
			} else {
				int otherValue = array[index + 1];
				
				if (value <= otherValue) {
					min = min(min, value);
					max = max(max, otherValue);
				} else {
					min = min(min, otherValue);
					max = max(max, value);
				}
			}
		}
		
		return new Point(min, max);
	}
}

