import java.io.IOException;
import java.io.InputStream;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashSet;
import java.util.NoSuchElementException;
import java.util.Set;

class FastScanner {
    private static FastScanner instance = null;
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private FastScanner() {} // 外部から new できないようにする
    public static FastScanner getInstance() {
        if (instance == null) {
            instance = new FastScanner();
        }
        return instance;
    }
    private boolean hasNextByte() {
        if (ptr < buflen) return true;
        ptr = 0;
        try {
            buflen = in.read(buffer);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return buflen > 0;
    }
    private int readByte() {
        if (hasNextByte()) return buffer[ptr++];
        else return -1;
    }
    private boolean isPrintableChar(int c) {
        return 33 <= c && c <= 126;
    }
    public boolean hasNext() {
        while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
        return hasNextByte();
    }
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while (isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        while (b >= '0' && b <= '9') {
            n = n * 10 + (b - '0');
            b = readByte();
        }
        return minus ? -n : n;
    }
    public int nextInt() {
        return (int) nextLong();
    }
    public long[] nextLongs(int n) {
    	long[] a = new long[n];
    	for (int i = 0; i < n; ++i) {
    		a[i] = nextLong();
    	}
    	return a;
    }
    public int[] nextInts(int n) {
    	int[] a = new int[n];
    	for (int i = 0; i < n; ++i) {
    		a[i] = nextInt();
    	}
    	return a;
    }
}

class MyPrintWriter extends PrintWriter {
    public MyPrintWriter(PrintStream out) {
        super(out);
    }
    public void print(long[] a) {
    	print(a, " ");
    }
    public void print(int[] a) {
    	print(a, " ");
    }
    public void print(int[] a, String separator) {
    	for (int i = 0; i < a.length; ++i) {
    		super.print(a[i]+(i==a.length-1?"\n":separator));
    	}
    }
    public void print(long[] a, String separator) {
    	for (int i = 0; i < a.length; ++i) {
    		super.print(a[i]+(i==a.length-1?"\n":separator));
    	}
    }
    public void printlnYesNo(boolean flag) {
    	println(flag?"Yes":"No");
    }
}

class Main implements Runnable { // Runnableを実装する
	public static void main(String[] args) {
		new Thread(null, new Main(), "", 1024 * 1024 * 1024).start(); // 1024MBスタックを確保して実行
	}
	public void run() {
		FastScanner sc = FastScanner.getInstance();
		MyPrintWriter pw = new MyPrintWriter(System.out);
		int N=sc.nextInt();
		int ans=0;
		for(int i=1;i<=N;++i) {
			boolean ok=false;
			int a=i;
			while(a>0) {
				ok|=a%10==8;
				a/=10;
			}
			if(ok)++ans;
		}
		System.out.println(ans);
		pw.close();
	}
	static void tr(Object...objects) {System.out.println(Arrays.deepToString(objects));}
}