A newspaper is published in Walrusland. Its heading is s1, it consists of lowercase Latin letters. Fangy the little walrus wants to buy several such newspapers, cut out their headings, glue them one to another in order to get one big string. After that walrus erase several letters from this string in order to get a new word s2. It is considered that when Fangy erases some letter, there's no whitespace formed instead of the letter. That is, the string remains unbroken and it still only consists of lowercase Latin letters.

For example, the heading is "abc". If we take two such headings and glue them one to the other one, we get "abcabc". If we erase the letters on positions 1 and 5, we get a word "bcac".

Which least number of newspaper headings s1 will Fangy need to glue them, erase several letters and get word s2?

Input

The input data contain two lines. The first line contain the heading s1, the second line contains the word s2. The lines only consist of lowercase Latin letters (1 ≤ |s1| ≤ 104, 1 ≤ |s2| ≤ 106).

Output

If it is impossible to get the word s2 in the above-described manner, print "-1" (without the quotes). Otherwise, print the least number of newspaper headings s1, which Fangy will need to receive the word s2.

Examples

Input

abc
xyz


Output

-1


Input

abcd
dabc


Output

2


import java.awt.Point;
import java.io.*;
import java.math.BigInteger;
import java.util.*;
import static java.lang.Math.*;

public class ProblemC_75 {
    
    final boolean ONLINE_JUDGE = System.getProperty("ONLINE_JUDGE")!=null;
    BufferedReader in;
    PrintWriter out;
    StringTokenizer tok = new StringTokenizer("");
    
    void init() throws FileNotFoundException{
        if (ONLINE_JUDGE){
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
        }else{
            in = new BufferedReader(new FileReader("input.txt"));
            out = new PrintWriter("output.txt");
        }
    }
    
    String readString() throws IOException{
        while(!tok.hasMoreTokens()){
            tok = new StringTokenizer(in.readLine());
        }
        return tok.nextToken();
    }
    
    int readInt() throws IOException{
        return Integer.parseInt(readString());
    }
    
    long readLong() throws IOException{
        return Long.parseLong(readString());
    }
    
    double readDouble() throws IOException{
        return Double.parseDouble(readString());
    }
    
    public static void main(String[] args){
        new ProblemC_75().run();
    }
    
    public void run(){
        try{
            long t1 = System.currentTimeMillis();
            init();
            solve();
            out.close();
            long t2 = System.currentTimeMillis();
            System.err.println("Time = "+(t2-t1));
        }catch (Exception e){
            e.printStackTrace(System.err);
            System.exit(-1);
        }
    }
    
    void solve() throws IOException{
        char[] s1 = in.readLine().toCharArray();
        int n = s1.length;
        int[][] a = new int[26][n];
        for (int i = 0; i < 26; i++){
            Arrays.fill(a[i], -1);
        }
        a[s1[n-1]-'a'][n-1] = n - 1;
        for (int i = n - 2; i >= 0; i--){
            for (int j = 0; j < 26; j++){
                if (j == s1[i] - 'a') a[j][i] = i;
                else a[j][i] = a[j][i+1];
            }
        }
        char[] s2 = in.readLine().toCharArray();
        long count = 0;
        int cur = -1;
        for (int i = 0; i < s2.length; i++){
            int j = s2[i] - 'a';
            if (a[j][0] == -1){
                out.print(-1);
                return;
            }
            cur = (cur + 1) % n;
            if (cur == 0) count++;
            if (a[j][cur] == -1){
                cur = a[j][0];
                count++;
            }else cur = a[j][cur];
        }
        out.print(count);
    }
    
    static int[][] step8 = {{-1, 0}, {1, 0}, {0, -1}, {0, 1}, {-1, -1}, {1, -1}, {-1, 1}, {1, 1}};
    
    static int[][] stepKnight = {{-2, -1}, {-2, 1}, {-1, -2}, {-1, 2}, {1, -2}, {1, 2}, {2, -1}, {2, 1}};
    
    static long gcd(long a, long b){
        if (a == 0) return b;
        return gcd(b % a, a);
    }
    
    static long lcm(long a, long b){
        return a / gcd(a, b)*b;
    }

    static long[] gcdPlus(long a, long b){
        long[] d = new long[3];
        if (a == 0){
            d[0] = b;
            d[1] = 0;
            d[2] = 1;
        }else{
            d = gcdPlus(b % a, a);
            long r = d[1];
            d[1] = d[2] - b/a*d[1];
            d[2] = r;
        }
        return d;
    }
    
    static long binpow(long a, int n){
        if (n == 0) return 1;
        if ((n & 1) == 0){
            long b = binpow(a, n/2);
            return b*b;
        }else return binpow(a, n - 1)*a;
    }
    
    static long binpowmod(long a, int n, long m){
        if (m == 1) return 0;
        if (n == 0) return 1;
        if ((n & 1) == 0){
            long b = binpowmod(a, n/2, m);
            return (b*b) % m;
        }else return binpowmod(a, n - 1, m)*a % m;
    }
    
    static long phi(long n){
        int[] p = Sieve((int)ceil(sqrt(n)) + 2);
        long phi = 1;
        for (int i = 0; i < p.length; i++){
            long x = 1;
            while (n % p[i] == 0){
                n /= p[i];
                x *= p[i];
            }
            phi *= x - x/p[i];
        }
        if (n != 1) phi *= n - 1;
        return phi;
    }
    
    static long f(long n, int x, int k){ //Кол-во десятичных чисел (включая 0), содержащих в себе цифры от 0 до k-1
        if (n == 0) return 1;
        long b = binpow(10, x - 1);
        long c = n / b;
        return (c < k? c: k)*binpow(k, x - 1) + (c < k? 1: 0)*f(n % b, x - 1, k);
    }
    
    static long fib(int n){
        if (n == 0) return 0;
        if ((n & 1) == 0){
            long f1 = fib(n/2 - 1);
            long f2 = fib(n/2 + 1);
            return f2*f2 - f1*f1;
        }else{
            long f1 = fib(n/2);
            long f2 = fib(n/2 + 1);
            return f1*f1 + f2*f2;
        }
    }
    
    static BigInteger BigFib(int n){
        if (n == 0) return BigInteger.ZERO;
        if ((n & 1) == 0){
            BigInteger f1 = BigFib(n/2 - 1);
            f1 = f1.multiply(f1);
            BigInteger f2 = BigFib(n/2 + 1);
            f2 = f2.multiply(f2);
            return f2.subtract(f1);
        }else{
            BigInteger f1 = BigFib(n/2);
            f1 = f1.multiply(f1);
            BigInteger f2 = BigFib(n/2 + 1);
            f2 = f2.multiply(f2);
            return f2.add(f1);
        }
    }
    
    static public class PointD{
        
        double x, y;
        
        public PointD(double x, double y){
            this.x = x;
            this.y = y;
        }
    }
    
    static double d(Point p1, Point p2){
        return sqrt(d2(p1, p2));
    }
    
    static public double d(PointD p1, PointD p2){
        return sqrt(d2(p1, p2));
    }
    
    static double d2(Point p1, Point p2){
        return (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
    }
    
    static public double d2(PointD p1, PointD p2){
        return (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
    }
    
    static boolean IsProbablyPrime(long n){
        if (n == 1) return false;
        if ((n & 1) == 0) return false;
        for (int j = 3; j < sqrt(n) + 1; j += 2){
            if (n % j == 0) return false;
        }
        return true;
    }

    static int[] Sieve(int n){
        boolean[] b = new boolean[n+1];
        Arrays.fill(b, true);
        b[0] = false;
        b[1] = false;
        long nLong = n;
        int j=0;
        for (int i = 1; i <= n; i++) {
            if (b[i]){
                j++;
                if (((long)i)*i <= nLong) {
                    for (int k = i*i; k <= n; k += i) {
                        b[k] = false;
                    }
                }
            }
        }
        int[] p = new int[j];
        Arrays.fill(p, 0);
        j=0;
        for (int i = 2; i <= n; i++) {
            if (b[i]){
                p[j]=i;
                j++;
            }
        }
        return p;
    }
    
    static int[][] Palindromes(String s){
        char[] c = s.toCharArray();
        int n = c.length;
        int[][] d = new int[2][n];
        int l = 0, r = -1;
        for (int i = 0; i < n; i++){
            int j = (i > r? 0: min(d[0][l+r-i+1], r-i+1)) + 1;
            for (; i - j >= 0 && i + j - 1< n && c[i-j] == c[i+j-1]; j++);
            d[0][i] = --j;
            if (i + d[0][i] - 1 > r){
                r = i + d[0][i] - 1;
                l = i - d[0][i];
            }
        }
        l = 0;
        r = -1;
        for (int i = 0; i < n; i++){
            int j = (i > r? 0: min(d[1][l+r-i], r-i)) + 1;
            for (; i - j >= 0 && i + j < n && c[i-j] == c[i+j]; j++);
            d[1][i] = --j;
            if (i + d[1][i] > r){
                r = i + d[1][i];
                l = i - d[1][i];
            }
        }
        return d;
    }
    
    static public class Permutation {
        
        int[] a;
        int n;
        
        public Permutation(int n){
            this.n=n;
            a=new int[n];
            for (int i=0; i<n; i++){
                a[i]=i;
            }
        }
        
        public boolean nextPermutation(){ //Пишется с do{}while(nextPermutation(a));
            int i=n-1;
            for (i=n-2; i>=0; i--){
                if (a[i]<a[i+1]){
                    break;
                }
            }
            if (i==-1){
                return false;
            }
            int jMin=i+1;
            for (int j=n-1; j>i; j--){
                if (a[i]<a[j]&&a[j]<a[jMin]){
                    jMin=j;
                }
            }
            swap(i, jMin);
            for (int j=1; j<=(n-i)/2; j++){
                swap(i+j, n-j);
            }
            return true;
        }
        
        
        public int get(int i){
            return a[i];
        }
        
        void swap(int i, int j){
            int r=a[i];
            a[i]=a[j];
            a[j]=r;
        }
    }
    
    static public class Fraction implements Comparable<Fraction>, Cloneable{
        
        public final Fraction FRACTION_ZERO = new Fraction();
        public final Fraction FRACTION_ONE = new Fraction(1);
        public long numerator = 0;
        public long denominator = 1;
        
        public Fraction(){
            numerator = 0;
            denominator = 1;
        }
        
        public Fraction(long numerator){
            this.numerator = numerator;
            denominator = 1;
        }
        
        public Fraction(long numerator, long denominator){
            this.numerator = numerator;
            this.denominator = denominator;
            Cancellation();
        }
        
        public Fraction(double numerator, double denominator, int accuracy){
            this.numerator = (long)(numerator*pow(10,accuracy));
            this.denominator = (long)(denominator*pow(10,accuracy));
            Cancellation();
        }
        
        public Fraction(String s){
            if (s.charAt(0) == '-'){
                denominator = -1;
                s = s.substring(1);
            }
            if (s.indexOf("/") != -1){
                denominator *= Integer.parseInt(s.substring(s.indexOf("/") + 1));
            }
            if (s.indexOf(" ") != -1){
                numerator = Integer.parseInt(s.substring(0, s.indexOf(" "))) * abs(denominator) + Integer.parseInt(s.substring(s.indexOf(" ") + 1, s.indexOf("/")));
            }else{
                if (s.indexOf("/") != -1){
                    numerator = Integer.parseInt(s.substring(0, s.indexOf("/")));
                }else{
                    numerator = Integer.parseInt(s)*abs(denominator);
                }
            }
            this.Cancellation();
        }
        
        void Cancellation(){
            long g = gcd(abs(numerator), abs(denominator));
            numerator /= g;
            denominator /= g;
            if (denominator < 0){
                numerator *= -1;
                denominator *= -1;
            }
        }
        
        public String toString(){
            String s = "";
            if (numerator == 0){
                return "0";
            }
            if (numerator < 0){
                s += "-";
            }
            if (abs(numerator) >= denominator){
                s += Long.toString(abs(numerator) / denominator) + " ";
            }
            if (abs(numerator) % denominator != 0){
                s += Long.toString(abs(numerator) % denominator);
            }else{
                s = s.substring(0, s.length()-1);
            }
            if (denominator != 1){
                s += "/" + Long.toString(denominator);
            }
            return s;
        }
        
        public Fraction add(Fraction f){
            Fraction fResult = new Fraction();
            fResult.denominator = lcm(denominator, f.denominator);
            fResult.numerator = numerator * fResult.denominator / denominator + f.numerator * fResult.denominator / f.denominator;
            fResult.Cancellation();
            return fResult;
        }
        
        public Fraction subtract(Fraction f){
            Fraction fResult = new Fraction();
            fResult.denominator = lcm(denominator, f.denominator);
            fResult.numerator = numerator * fResult.denominator / denominator - f.numerator * fResult.denominator / f.denominator;
            fResult.Cancellation();
            return fResult;
        }
        
        public Fraction multiply(Fraction f){
            Fraction fResult = new Fraction();
            fResult.numerator = numerator * f.numerator;
            fResult.denominator = denominator * f.denominator;
            fResult.Cancellation();
            return fResult;
        }
        
        public Fraction divide(Fraction f){
            Fraction fResult = new Fraction();
            fResult.numerator = numerator * f.denominator;
            fResult.denominator = denominator * f.numerator;
            fResult.Cancellation();
            return fResult;
        }
        
        @Override
        public int compareTo(Fraction f){
            long g = gcd(denominator, f.denominator);
            long res = numerator * (f.denominator / g) - f.numerator * (denominator / g);
            if (res < 0){
                return -1;
            }
            if (res > 0){
                return 1;
            }
            return 0;
        }
        
        public Fraction clone(){
            Fraction fResult = new Fraction(numerator, denominator);
            return fResult;
        }
        
        public Fraction floor(){
            Fraction fResult = this.clone();
            fResult.numerator = (fResult.numerator / fResult.denominator) * fResult.denominator;
            return fResult;
        }
        
        public Fraction ceil(){
            Fraction fResult = this.clone();
            fResult.numerator = (fResult.numerator/fResult.denominator + 1) * fResult.denominator;
            return fResult;
        }
        
        public Fraction binpow(int n){
            if (n==0) return FRACTION_ONE;
            if ((n&1)==0){
                Fraction f=this.binpow(n/2);
                return f.multiply(f);
            }else return binpow(n-1).multiply(this);
        }
    }
    
    static public class FenwickTree_1{  //One-dimensional array     
        
        int n;
        long[] t;
        
        public FenwickTree_1(int n){
            this.n = n;
            t = new long[n];
        }
        
        public long sum(int xl, int xr){
            return sum(xr) - sum(xl);
        }
        
        public long sum(int x){
            long result = 0;
            for (int i = x; i >= 0; i = (i & (i + 1)) - 1){
                result += t[i];
            }
            return result;
        }
        
        public void update(int x, long delta){
            for (int i = x; i < n; i = (i | (i + 1))){
                t[i] += delta;
            }
        }
    }
    
    static public class FenwickTree_2{  //Two-dimensional array
        
        int n, m;
        long[][] t;
        
        public FenwickTree_2(int n, int m){
            this.n = n;
            this.m = m;
            t = new long[n][m];
        }
        
        public long sum(int xl, int yl, int xr, int yr){
            return sum(xr, yr) - sum(xl - 1, yr) - sum(xr, yl - 1) + sum(xl - 1, yl - 1);
        }
        
        public long sum(int x, int y){
            long result = 0;
            for (int i = x; i >= 0; i = (i & (i + 1)) - 1){
                for (int j = y; j >= 0; j = (j & (j + 1)) - 1){
                    result+=t[i][j];
                }
            }
            return result;
        }
        
        public void update(int x, int y, long delta){
            for (int i = x; i < n; i = (i | (i + 1))){
                for (int j = y; j < m; j = (j | (j + 1))){
                    t[i][j] += delta;
                }
            }
        }
    }
    
    static public class FenwickTree_3{  //Three-dimensional array
        
        int n, m, l;
        long[][][] t;
        
        public FenwickTree_3(int n, int m, int l){
            this.n = n;
            this.m = m;
            this.l = l;
            t = new long[n][m][l];
        }
        
        public long sum(int xl, int yl, int zl, int xr, int yr, int zr){
            return sum(xr, yr, zr) - sum(xl - 1, yr, zr)
            + sum(xl - 1, yr, zl - 1) - sum(xr, yr, zl - 1)
            - sum(xr, yl - 1, zr) + sum(xl - 1, yl - 1, zr)
            - sum(xl - 1, yl - 1, zl - 1) + sum(xr, yl - 1, zl - 1);
        }
        
        public long sum(int x, int y, int z){
            long result = 0;
            for (int i = x; i >= 0; i = (i & (i + 1)) - 1){
                for (int j = y; j >= 0; j = (j & (j + 1)) - 1){
                    for (int k = z; k >= 0; k = (k & (k + 1)) - 1){
                        result += t[i][j][k];
                    }
                }
            }
            return result;
        }
        
        public void update(int x, int y, int z, long delta){
            for (int i = x; i < n; i = (i | (i + 1))){
                for (int j = y; j < n; j = (j | (j + 1))){
                    for (int k = z; k < n; k = (k | (k + 1))){
                        t[i][j][k] += delta;
                    }
                }
            }
        }
    }
}

