bcdef
abbbc
 z
y
 reddit
abcdef
 abc
aaa
 y
z
 cbxz
aaaa

bccdb
 z
 dfdeed
 aab
 y
 abac

		
		
			import java.io.*;
		import java.math.BigInteger;
		import java.util.*;
			
			
			public class Practice {
				private static InputStream stream;
				private static byte[] buf = new byte[1024];
				private static int curChar;
				private static int numChars;
				private static SpaceCharFilter filter;
				private static PrintWriter pw;
				private static long mod=1000000007;
			
			    public static void main(String[] args) {
			    	InputReader(System.in);
					pw = new PrintWriter(System.out); 
			        new Thread(null ,new Runnable(){
			           public void run(){
			               try{
			                   solve();//This is solution method
		               pw.close();
		           } catch(Exception e){
		               e.printStackTrace();
		           }
		       }
		   },"1",1<<26).start();
			    				   }
			    				    static long sort(int a[])
			        		    	{  int n=a.length;
			        		    		int b[]=new int[n];	
			        		    		return mergeSort(a,b,0,n-1);}
			        		    	static long mergeSort(int a[],int b[],long left,long right)
			        		    	{ long c=0;if(left<right)
			        		    	 {   long mid=left+(right-left)/2;
			        		    		 c= mergeSort(a,b,left,mid);
			        		    		 c+=mergeSort(a,b,mid+1,right);
			        		    		 c+=merge(a,b,left,mid+1,right); }	
			        		    		return c;	 }
			        		    	static long merge(int a[],int  b[],long left,long mid,long right)
			        		    	{long c=0;int i=(int)left;int j=(int)mid; int k=(int)left;
			        		    	while(i<=(int)mid-1&&j<=(int)right)
			        		    	{ if(a[i]>a[j]) {b[k++]=a[i++]; }
			        		    	else	{ b[k++]=a[j++];c+=mid-i;}}
			        		    	while (i <= (int)mid - 1)   b[k++] = a[i++]; 
			        		    	while (j <= (int)right) b[k++] = a[j++];
			        		    	for (i=(int)left; i <= (int)right; i++) 
			        		    		a[i] = b[i];  return c;  }
			        		    		    
			    				    
	    				    
	        		    	public static void solve() {
	        		    		char[] olega = nextLine().toCharArray();
	        		            char[] igora = nextLine().toCharArray();
	        		            int n = olega.length;

	        		            Arrays.sort(olega);
	        		            Arrays.sort(igora);
	        		            char[] igorn = new char[igora.length];
	        		            for (int i = 0; i < igora.length; i++) {
	        		                igorn[i] = igora[igora.length - 1 - i];
	        		            }
	        		            olega = Arrays.copyOf(olega, n / 2 + (n % 2 == 0 ? 0 : 1));
	        		            igorn = Arrays.copyOf(igorn, n / 2);
	        		            char[] olegn = reverse(olega);
	        		            igora = reverse(igorn);

	        		            int i = 0;
	        		            int oli = 0;
	        		            int igi = 0;
	        		            char[] res = new char[n];
	        		            while (i < n) {
	        		                if (oli < olega.length && igi < igorn.length && olega[oli] >= igorn[igi]) {
	        		                    break;
	        		                }
	        		                if (i % 2 == 0) res[i] = olega[oli++]; else res[i] = igorn[igi++];
	        		                i++;
	        		            }

	        		            oli = 0;
	        		            igi = 0;
	        		            int finish = i;
	        		            for (int j = n - 1; j >= finish; j--) {
	        		                if (i % 2 == 0) res[j] = olegn[oli++]; else res[j] = igora[igi++];
	        		                i++;
	        		            }
	        		            pw.println(String.valueOf(res));

	        		        }

	        		        static char[] reverse(char[] a) {
	        		            char[] r = new char[a.length];
	        		            for (int i = 0; i < a.length; i++) r[i] = a[a.length - 1 - i];
	        		            return r;
	        		        }
	        		    	 	
        		    		
		        		    		
		        		    				
		        		        
		public static boolean isVowel(char c){        		    		
			if(c=='a' || c=='i'|| c=='e' || c=='o' || c=='u')
					return true;
				return false;
			}
			
			public static long trailingZeroes(long n) {
			    long count = 0;
		
			    while (n > 0) {
			        n /= 5;
			        count += n;
			    }
		
			    return count;
			}
		
		    public static int largestPrimeFactor(long number) {
		        int i;
		
		        for (i = 2; i <= number; i++) {
		            if (number % i == 0) {
		                number /= i;
		                i--;
		            }
		        }
		
		        return i;
		}
		   
			
		    public static String reverseString(String s) {
				StringBuilder sb = new StringBuilder(s);
				sb.reverse();
				return (sb.toString());
			}
		    private static BigInteger ncr(int n,int k){
		    	if (k < 0 || k > n) return BigInteger.ZERO;
		        if (n-k < k) k = n-k;
		
		        BigInteger x = BigInteger.ONE;
		        for (int i = 1; i <= k; i++) {
		            x = x.multiply(new BigInteger(""+(n-i+1)));
		x = x.divide(new BigInteger(""+i));
		        }
		
		return x;
		    }
		    static long fact[];
		private static void factmod(int n,int mod){
			fact=new long[n+1];
			fact[0]=1;
			for(int i=1;i<=n;i++){
				fact[i]=i*fact[i-1];
				//fact[i]%=mod;
		
			}
			
		}
		private static long phi(long n){
			long ans=n;
			if(n%2==0)
				ans-=(ans/2);
			while(n%2==0)
			{
				n/=2;
				
			}
			for(int i=3;i*i<=n;i+=2){
				if(n%i==0){
				while(n%i==0){
					n/=i;
				}
				ans-=(ans/i);
				}
			}
			if(n>2)
				ans-=(ans/n);
			
			return ans;
		}
		static long d,x,y;
		static long modInverse(long A, long M)
		{
		extendedEuclid(A,M);
		return (x%M+M)%M;    //x may be negative
		}
		static void extendedEuclid(long A, long B) {
		if(B == 0) {
		d = A;
		x = 1;
		y = 0;
		}
		else {
		extendedEuclid(B, A%B);
		long temp = x;
		x = y;
		y = temp - (A/B)*y;
		}
		}
		static boolean prime[];
		static int spf[];
		public static void sieve(int n){
			prime=new boolean[n+1];
			spf=new int[n+1];
			
			Arrays.fill(spf, 1);
			Arrays.fill(prime, true);
		prime[1]=false;
			spf[2]=2;
			for(int i=4;i<=n;i+=2)
			{
				spf[i]=2;
				prime[i]=false;
			}
		
		for(int i=3;i<=n;i+=2){
			if(prime[i]){
				spf[i]=i;
				for(int j=2*i;j<=n;j+=i){
					
					prime[j]=false;
				if(spf[j]==1){
					spf[j]=i;
				}
				}
			}
		}
			
		}
		public static boolean isPrime(long n) {
			
			if (n <= 1)
				return false;
			if (n <= 3)
				return true;
		
			if (n % 2 == 0 || n % 3 == 0)
				return false;
		
			for (long i = 5; i * i <= n; i = i + 6)
				if (n % i == 0 || n % (i + 2) == 0)
					return false;
		
			return true;
		}
		
		    public static long pow(long n, long p,long mod) {
				if(p==0)
					return 1;
				if(p==1)
					return n%mod;
				if(p%2==0){
					long temp=pow(n, p/2,mod);
				return (temp*temp)%mod;
				}else{
					 	long temp=pow(n,p/2,mod);
					 	temp=(temp*temp)%mod;
					 	return(temp*n)%mod;
					 	
				}
			}
			public static long gcd(long x, long y) {
				if (x == 0)
					return y;
				else
					return gcd( y % x,x);
			}
			
			
			public static void InputReader(InputStream stream1) {
				stream = stream1;
			}
		 
			private static boolean isWhitespace(int c) {
				return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
			}
		 
			private static boolean isEndOfLine(int c) {
				return c == '\n' || c == '\r' || c == -1;
			}
		 
			private static int read() {
				if (numChars == -1)
					throw new InputMismatchException();
				if (curChar >= numChars) {
					curChar = 0;
					try {
						numChars = stream.read(buf);
					} catch (IOException e) {
						throw new InputMismatchException();
					}
					if (numChars <= 0)
						return -1;
				}
				return buf[curChar++];
			}
		 
			private static int nextInt() {
				int c = read();
				while (isSpaceChar(c))
					c = read();
				int sgn = 1;
				if (c == '-') {
			sgn = -1;
			c = read();
		}
		int res = 0;
		do {
			if (c < '0' || c > '9')
			throw new InputMismatchException();
		res *= 10;
		res += c - '0';
					c = read();
				} while (!isSpaceChar(c));
				return res * sgn;
			}
		 
			private static long nextLong() {
				int c = read();
				while (isSpaceChar(c))
					c = read();
				int sgn = 1;
				if (c == '-') {
			sgn = -1;
			c = read();
		}
		long res = 0;
		do {
			if (c < '0' || c > '9')
			throw new InputMismatchException();
		res *= 10;
		res += c - '0';
					c = read();
				} while (!isSpaceChar(c));
				return res * sgn;
			}
		 
			private static String nextToken() {
				int c = read();
				while (isSpaceChar(c))
					c = read();
				StringBuilder res = new StringBuilder();
				do {
					res.appendCodePoint(c);
					c = read();
				} while (!isSpaceChar(c));
				return res.toString();
			}
		 
			private static String nextLine() {
				int c = read();
				while (isSpaceChar(c))
					c = read();
				StringBuilder res = new StringBuilder();
				do {
					res.appendCodePoint(c);
					c = read();
				} while (!isEndOfLine(c));
				return res.toString();
			}
		 
			private static int[] nextIntArray(int n) {
				int[] arr = new int[n];
				for (int i = 0; i < n; i++) {
					arr[i] = nextInt();
				}
				return arr;
			}
		 
			private static int[][] next2dArray(int n, int m) {
				int[][] arr = new int[n][m];
				for (int i = 0; i < n; i++) {
					for (int j = 0; j < m; j++) {
						arr[i][j] = nextInt();
					}
				}
				return arr;
			}
			private static char[][] nextCharArray(int n,int m){
				char [][]c=new char[n][m];
				for(int i=0;i<n;i++){
					String s=nextLine();
					for(int j=0;j<s.length();j++){
						c[i][j]=s.charAt(j);
					}
				}
				return c;
			}
		 
			private static long[] nextLongArray(int n) {
				long[] arr = new long[n];
				for (int i = 0; i < n; i++) {
					arr[i] = nextLong();
				}
				return arr;
			}
		 
			private static void pArray(int[] arr) {
				for (int i = 0; i < arr.length; i++) {
					pw.print(arr[i] + " ");
				}
				pw.println();
				return;
			}
		 
			private static void pArray(long[] arr) {
				for (int i = 0; i < arr.length; i++) {
					pw.print(arr[i] + " ");
				}
				pw.println();
				return;
			}
		 
			private static void pArray(boolean[] arr) {
				for (int i = 0; i < arr.length; i++) {
					pw.print(arr[i] + " ");
				}
				pw.println();
				return;
			}
		 
			private static boolean isSpaceChar(int c) {
				if (filter != null)
					return filter.isSpaceChar(c);
				return isWhitespace(c);
			}
		 
			private interface SpaceCharFilter {
				public boolean isSpaceChar(int ch);
			}
		
			
		}	
		
	/*class Pair implements Comparable<Pair>{
		
			
			int  bea,pri;
			Pair(int bea,int pri){
			
				this.bea=bea;
				this.pri=pri;
				
			}
			@Override
			public int compareTo(Pair o) {
		
				return 0;
				//return (int)(o.size-size);
			}
			public int hashCode() {
					//int hu = (int) (x ^ (x >>> 32));
					//int hv = (int) (y ^ (y >>> 32));
					//int hw = (int) (mass ^ (mass >>> 32));
					//return 31 * hu + hv ;
				return 0;
				}
				public boolean equals(Object o) {
					Pair other = (Pair) o;
				//	return x == other.x && y == other.y;
				return false;
				}
		}
		*/
