import java.io.*;
import java.util.Scanner;
public class Cwk1Problem6 {

    /**
     * @param args the command line arguments
     */

    public static void main(String[] args) throws FileNotFoundException {
                //Set up scanner.
        String filename = "Input.txt";
        Scanner input = new Scanner(new File(filename));

        //Get the text and pattern as strings.
        String text = input.nextLine();
        String pattern = input.nextLine();

        //Close the input file.
        input.close();
        //Find the next highest power of 2 above the current length.
        double power = Math.ceil(Math.log(text.length())/Math.log(2));
        double length = Math.pow(2, power);

        Complex[] t = new Complex[(int)length];
        Complex[] tSquared = new Complex[(int) length];
        Complex[] tCubed = new Complex[(int) length];
        Complex[] p = new Complex[(int) length];
        Complex[] pSquared = new Complex[(int) length];
        Complex[] pCubed = new Complex[(int)length];

        for (int i = 0; i<pattern.length(); i++)
        {
            //Inverse fills t, tSquared and tCubed.
            if (text.charAt(text.length()-i-1) == 63)
            {
                t[i]=new Complex(0,0);
            }
            else t[i] = new Complex(text.charAt(text.length()-i-1),0);

            tSquared[i]  = new Complex(Math.pow(t[i].returnReal(),2) ,0);
            tCubed[i] = new Complex(Math.pow(t[i].returnReal(),3) ,0);
            //fills p, pSquared and PCubed
            if (pattern.charAt(i) == 63)
            {
                p[i]=new Complex(0,0);
            }
            else p[i] = new Complex(pattern.charAt(i),0);
            pSquared[i]=new Complex(Math.pow(p[i].returnReal(),2),0);
            pCubed[i]=new Complex(Math.pow(p[i].returnReal(),3),0);
        }
        for (int i=pattern.length(); i<text.length(); i++)
        {
           // Inverse fills t, tSquared and tCubed.
           if (text.charAt(text.length()-i-1) == 63)
            {
                t[i]=new Complex(0,0);
            }
            else {t[i] = new Complex(text.charAt(text.length()-i-1),0);}
           tSquared[i]  = new Complex(Math.pow(t[i].returnReal(),2) ,0);
           tCubed[i] = new Complex(Math.pow(t[i].returnReal(),3) ,0);
           //Sets all p's as (0,0) as padding.
           p[i] = new Complex(0,0);
           pSquared[i] = new Complex(0,0);
           pCubed[i] = new Complex(0,0);
        }
        //Sets everything as (0,0) as padding.
        for (int i = text.length(); i<length; i++)
        {
            t[i] = new Complex(0,0);
            tSquared[i] = new Complex(0,0);
            tCubed[i] = new Complex(0,0);
            p[i] = new Complex(0,0);
            pSquared[i] = new Complex(0,0);
            pCubed[i] = new Complex(0,0);
        }

        Complex[] firstFourierOutput = FFT.multiplyPoly(pCubed,t,t.length);
        Complex[] secondFourierOutput = FFT.multiplyPoly(pSquared, tSquared, t.length);
        Complex[] thirdFourierOutput = FFT.multiplyPoly(p, tCubed, t.length);
        int[] firstSum = new int[text.length()-pattern.length()+1];
        int[] secondSum = new int[text.length() - pattern.length()+1];
        int[] thirdSum = new int [text.length()-pattern.length()+1];
        boolean result = false;
        for (int i=0; i<=text.length()-pattern.length(); i++)
        {
            firstSum[i] = (int)firstFourierOutput[text.length()-i-1].returnReal();
            secondSum[i] = (int)secondFourierOutput[text.length()-i-1].returnReal();
            thirdSum[i] = (int)thirdFourierOutput[text.length()-i-1].returnReal();

            if(firstSum[i]-2*secondSum[i]+thirdSum[i] == 0)
            {
                System.out.print(i);
                result = true;
                break;
            }
        }
        if (result == false) System.out.print("-1");
    }
}