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.io.*;
import java.math.BigInteger;
import java.util.*;
 
 
 
 public class Main {
	public static InputReader in;
    public static PrintWriter pw;
 
 
 
	public static void main(String args[]) {
		new Thread(null, new Runnable() {
            public void run() {
                try{
                    solve();
                }
                catch(Exception e){
                    e.printStackTrace();
                }
            }
        }, "1", 1 << 26).start();
    }
	static ArrayList<Integer> g[];
	static ArrayList<Integer> h[];
	static boolean visited[];
	static boolean visit[];
	static int par[];
	static int degree[];
	static int edjes=0;
	static int start=-1;
	static int end=-1;
	static int Total=0;
	static int time1[];
	static int time2[];
	static int glob=0;
	static long cnt=0;
	static boolean vis2[][];
	static int lev=1;
    static int depth[];
    static long[] sm;
    static int val[];
    static int len=0;
    static long sum1=0;
    static int pre[][];
 static HashMap<String,Integer> hm;
 //static TreeSet<Long> set;
 static boolean Not[];
 //static int pre[][];
 static int parent[];
 static HashSet<Integer> set[];
 static boolean bb=false;
    public static void solve(){
		
	
		 in = new InputReader(System.in);
	  	 pw = new PrintWriter(System.out);
	  	String s1=in.readString();
	  	String s2=in.readString();
	    TreeSet<Integer> set[]=new TreeSet[26];
	    for(int i=0;i<26;i++)
	    	set[i]=new TreeSet();
	    for(int i=0;i<s1.length();i++)
	    {
	    	set[s1.charAt(i)-'a'].add(i+1);
	    }
	    char c2[]=s2.toCharArray();
	    int index=-1;
	    boolean ans=false;
	    int an1=1;
	    for(int i=0;i<s2.length();i++)
	    {
	    	char c=s2.charAt(i);
	    	if(index==-1)
	    	{
	    	int next=set[c-'a'].size()!=0?(set[c-'a'].first()):-1;
	    	if(next==-1)
	    	{
	    		ans=true;
	    		break;
	    	}
	    	index=next;
	    	}
	    	else
	    	{
	    		int next=(set[c-'a'].higher(index)!=null)?set[c-'a'].higher(index):-1;
	    		if(next==-1)
	    		{
	    			an1++;
	    			index=set[c-'a'].size()!=0?(set[c-'a'].first()):-1;
	    			if(index==-1)
	    			{
	    				ans=true;break;
	    			}
	    		}
	    		else
	    		{
	    		index=next;	
	    		}
	    	}
	    }
	    if(ans)
	    	an1=-1;
	    System.out.println(an1);
    }
    private static int getParent(int x) {
    	while(parent[(int) x]!=x){
			parent[ (int) x] = parent[(int) parent[ (int) x]];
			x = parent[ (int) x];
		}
		return (int) x;
	}
	    
 /* private static boolean check(int mid, int[] a, int[] pr,int n) {
	
	  HashMap<Integer,Integer> hm=new HashMap();
	  
	  for(int i=1;i<=(mid+1);i++)
	  {
		  for(int x:set[i]){
		if(!hm.containsKey(x))
		  hm.put(x,1);
		else
			hm.put(x,hm.get(x)+1);
		if(hm.get(x)==(mid+1))
		{
			//System.out.println(i+" "+mid);
			//ana[i]=1;i
			return true;
		}
		  }
	  }
	  int now=1;
	  int then=mid+2;
	  while(then<=n)
	  {
		  for(int x:set[now])
		  {
			  if(hm.containsKey(x))
				  hm.put(x,hm.get(x)-1);
		  }
		  for(int x:set[then])
		  {
			  if(!hm.containsKey(x))
				  hm.put(x,1);
			  else
				  hm.put(x,hm.get(x)+1);
			  if(hm.get(x)==(mid+1))
			  {
				  
				  ana[now+1]=1;
				  return true;
			  }
		  }
		  now++;
		  then++;
	  }
	  
	return false;
}
  
 */
/*  public static int bfs(int x,int y,int tx,int ty,int n,int m)
    {
    		boolean vis[][]=new boolean[101][101];
    		vis[x][y]=true;
    		int lev=0;
    		Queue<String> Q=new LinkedList();
    		String sx=x+" "+y;
    		Q.add(sx);
    		while(!Q.isEmpty())
    		{
    			int count=Q.size();
    			while(count>0)
    			{
    				String p=Q.poll();
    				int i=Integer.parseInt(p.split(" ")[0]);
    				int j=Integer.parseInt(p.split(" ")[1]);
    				vis[i][j]=true;
    				if(i==tx&&j==ty)
    				{
    					return lev;
    				}
    				if(i==tx&&(j-1)==ty)
    				{
    					return lev;
    				}
    				if(i==tx&&(j+1)==ty)
    				{
    					return lev;
    				}
    				if((i+1)==tx&&(j)==ty)
    				{
    					return lev;
    				}
    				if((i-1)==tx&&(j)==ty)
    				{
    					return lev;
    				}
    				if(i<n&&j-1>=0&&!vis[i][j-1]&&a[i][j-1]=='O')
    				{
    					vis[i][j-1]=true;
    					String s=(i)+" "+(j-1);
    					Q.add(s);
    				}
    				if(i<n&&j+1<m&&!vis[i][j+1]&&a[i][j+1]=='O')
    				{
    					vis[i][j+1]=true;
    					String s=(i)+" "+(j+1);
    					Q.add(s);
    				}
    				if(i+1<n&&j<m&&!vis[i+1][j]&&a[i+1][j]=='O')
    				{
    					vis[i+1][j]=true;
    					String s=(i+1)+" "+j;
    					Q.add(s);
    				}
    				if(i-1>=0&&j<m&&!vis[i-1][j]&&a[i-1][j]=='O')
    				{
    					vis[i-1][j]=true;
    					String s=(i-1)+" "+j;
    					Q.add(s);
    				}
    				count--;
    			}
    			lev++;
    		//	System.out.println(Q);
    		}
    		return -1;
    }*/
    public static void dfs(int curr,int parent)
    {
    	visited[curr]=true;
    	par[curr]=parent;
    	for(int x:g[curr])
    	{
    		if(!visited[x])
    		{
    		depth[x]=depth[curr]+1;
    		dfs(x,curr);	
    		}
    	}
    		
    	
    }
  /*  public static void dfs2(int curr,int parent, HashSet<Integer> fk)
    {
    	visited[curr]=true;
    	fk.add(curr);
    	//System.out.print(curr+" ");
    	cnt++;
    	for(int x:g[curr])
    	{
    		if(x!=parent)
    		{
    			dfs2(x,par[x],fk);
    		}
    	}
    }*/
    /*public static void dfs1(int curr)
    {
    	visited[curr]=true;
    	long find=sm[curr]-(long)val[curr];
    	if(set.lower(find)!=null)
    	{
    		cnt+=(size[curr]);
    		return;
    	}
    	set.add(sm[curr]);
    	for(int x:g[curr])
    	{
    		if(!visited[x])
    			dfs1(x);
    	}
    	set.remove(sm[curr]);
    }
   /* public static void dfs(int curr,int parent)
    {
    	visited[curr]=true;
    	par[curr]=parent;
    	String s=curr+" "+parent;
    	sum1+=(hm.get(s));
    	size[curr]=1;
    	for(int x:g[curr])
    	{
    		if(!visited[x])
    		{
    			dfs(x,curr);
    			size[curr]+=size[x];
    		}
    	}
    	sm[curr]=sum1;
    	String p=curr+" "+parent;
    	sum1-=(hm.get(p));
    }
	public static int len(String s)
    {
    	
    	if(s.charAt(len++)=='l')
    	{
    		return 1;
    	}
    	else{
    		return Math.max(len(s), len(s))+1;
    	}
    }
    */
    
   public static int LCA(int p,int q)
    {
    	if(depth[p]<depth[q])
		{
			int tmp=p;
			p=q;
			q=tmp;
		}
		int dist=depth[p]-depth[q];
		while(dist>0)
		{
			int raise=(int)(Math.log(dist)/Math.log(2));
			p=pre[p][raise];
			dist-=(1<<raise);
		}
		if(p==q)
		{
			return p;
		}
		else{
		
		int current=(int)(Math.log(depth[p])/Math.log(2));
		for(int j=current;j>=0;j--)
		{
			if(pre[p][j]!=0&&pre[p][j]!=pre[q][j])
			{
				p=pre[p][j];
				q=pre[q][j];
			}
		}
		}
	return par[p];
    }
    
public static void dfs(int curr,int lev,int parent)
{
     visited[curr]=true;
     depth[curr]=lev;
     par[curr]=parent;
    // set[lev].add(curr);
     for(int x:g[curr])
     {
    	 if(!visited[x])
    	 {
    		 dfs(x,lev+1,curr);
    	 }
     }
     
}
 
 
	
 
 
 
 
     
        
     
        
 
   
/*public static void dfs2(int curr,int lev)
{
	time1[curr]=glob++;
	
	depth[curr]=lev;
	visited[curr]=true;
	nodes[lev].add(time1[curr]);
	values[lev].add(a[curr]);
	for(int x:g[curr])
	{
		if(!visited[x])
		{
			dfs2(x,lev+1);
		}
	}
time2[curr]=glob++;
}
 
 
 
public static void bfs1(int curr)
{
Queue<Integer> Q=new LinkedList<Integer>();
Q.add(1);
visit[1]=true;
int lev=2;
levels[1].add(1);
while(!Q.isEmpty())
{
	int cnt=Q.size();
	while(cnt>0)
	{
		int p=Q.poll();
		visit[p]=true;
		for(int x:g[p])
		{
			if(!visit[x])
			{
				Q.add(x);
				levels[lev].add(x);
			}
		}
		cnt--;
	}
	max=Math.max(lev, max);
	lev++;
}
}
 
 
	
 	private static long fact(int len) {
	long ans=1;
	for(int i=1;i<=len;i++)
		ans*=i;
	return ans;
}
 */
 
 
	
	// SubTree Checker DFS (TO CHECK IF X IS IN A SUBTREE OF Y)
	public static void dfs3(int curr)
	{
		visited[curr]=true;
		time1[curr]=glob++;
		for(int x:g[curr])
		{
		if(!visited[x])
			dfs3(x);
		}
		time2[curr]=glob++;
	}
    
	
	
 
    /*NO OF EDJES IN WHOLE CONNECTED COMPONENTS
  
	public static void dfs1(int curr)
	{
		visited[curr]=true;
		for(int next:g[curr])
		{
			edje++;
			if(!visited[next])
				dfs1(next);
		}
	}
	/*SUM OF ALL SUBTREE NODE'S VLAUES DFS
	public static void dfs(int curr,int prev)
		{
		val[curr]=1;
			for(int x:g[curr])
			{
				if(x!=prev)
				{
		            dfs(x,curr);
		            val[curr]+=val[x];
					
			    }
			}
		}*/
	
		public static long power(long a,long b)
		{
			long result=1;
			while(b>0)
			{
				if(b%2==1)
					result*=a;
				a=a*a;
				b/=2;
			}
			return result;
		}
				public static long pow(long n,long p,long m)
	{
		 long  result = 1;
		  if(p==0)
		    return 1;
		if (p==1)
		    return n;
		while(p!=0)
		{
		    if(p%2==1)
		        result *= n;
		    if(result>=m)
		    result%=m;
		    p >>=1;
		    n*=n;
		    if(n>=m)
		    n%=m;
		}
		return result;
	}
	static class Pair implements Comparable<Pair>{
	int x;
		int y;
		int val;
		Pair(int ver,int weight,int vl){
	     	this.x=ver;
			this.y=weight;
			this.val=vl;
			//this.index=index;
			
		}
		@Override
		public int compareTo(Pair o) {
		return o.val-this.val;
		}
				
	}
	public static long gcd(long a, long b) {
		  if (b == 0) return a;
		  return gcd(b, a%b);
		}
	static class InputReader {
 
		private InputStream stream;
		private byte[] buf = new byte[8192];
		private int curChar, snumChars;
		private SpaceCharFilter filter;
 
		public InputReader(InputStream stream) {
			this.stream = stream;
		}
 
		public int snext() {
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) {
				curChar = 0;
				try {
					snumChars = stream.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
 
		public   int nextInt() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
 
		public long nextLong() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
 
		public int[] nextIntArray(int n) {
			int a[] = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}
 
		public String readString() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isSpaceChar(c));
			return res.toString();
		}
 
		public boolean isSpaceChar(int c) {
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
 
		public interface SpaceCharFilter {
			public boolean isSpaceChar(int ch);
		}
	}
}