import java.io.File;
import java.io.FileNotFoundException;
import java.math.BigInteger;
import java.util.Scanner;

public class Main {
	
	private static Scanner sc;
	
	private static BigInteger getNum(String s, BigInteger p) {
		// TODO Auto-generated method stub
		int n = s.length();
		
		for(int i=n-1;i>=0;i--) {
			if(s.charAt(i)=='O') {
				p = p.subtract(new BigInteger("1"));
				if(!p.mod(new BigInteger("3")).equals(new BigInteger("0"))){
					return null;
				}
				
				p = p.divide(new BigInteger("3"));
				
				if(p.mod(new BigInteger("2")).equals(new BigInteger("0"))) {
					return null;
				}
			} else {
				p = p.multiply(new BigInteger("2"));
			}
		}
		
		return p;
	}
	
	private static String process(String s) {
		// TODO Auto-generated method stub
		int n = s.length();
		
		if(s.charAt(n-1) == 'E') {
			return "INVALID";
		}
		
		for(int i=0;i<n-1;i++) {
			if(s.charAt(i) == 'O' && s.charAt(i+1) == 'O') {
				return "INVALID";
			}
		}
		
		BigInteger p = new BigInteger("16");
		
		for(int i=4;i<=47;i++) {
			BigInteger m = getNum(s,p); 
			if(m != null) {
				return m.toString();
			}
			
			p = p.multiply(new BigInteger("2"));
		}
		
		return "INVALID";
	}

	public static void main(String[] args) throws FileNotFoundException {
		// TODO Auto-generated method stub
		sc = new Scanner(System.in);
		String s = sc.next();
		String ret = process(s);
		System.out.println(ret);
	}

}