import java.io.InputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Comparator;
import java.util.Deque;
import java.util.HashMap;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.Map;
import java.util.PriorityQueue;
import java.math.BigDecimal;
import java.math.BigInteger;
    
public class Main{

static final InputStream in=System.in;
static final PrintWriter out=new PrintWriter(System.out);
static final int INF=Integer.MAX_VALUE;
static final long LINF=Long.MAX_VALUE/2;
static int N,M,ans;
static int[] A,B;
static int[][] dp=new int[21][1<<20];

public static void main(String[] args) throws IOException{
InputReader ir=new InputReader(in);
N=ir.nextInt();
A=ir.nextIntArray(N);
M=ir.nextInt();
B=ir.nextIntArray(M);
Arrays.sort(B);
for(int i=0;i<=M;i++){
   Arrays.fill(dp[i],INF);
   dp[i][(1<<N)-1]=0;
}
for(int i=M-1;i>=0;i--){
   for(int j=(1<<N)-1;j>=0;j--){
      dp[i+1][j]=dp[i][j];
      for(int k=(1<<N)-1;k>=1;k--){
         if((j&k)!=0) continue;
         int sum=0;
         for(int l=0;l<N;l++){
            if((k&(1<<l))!=0) sum+=A[l];
         }
         if(B[i]<sum) continue;
         if(dp[i+1][j]>dp[i][j|k]+1) dp[i+1][j]=dp[i][j|k]+1;
      }
   }
}
ans=dp[M][0];
out.println(ans==INF?-1:ans);
out.flush();
}

static class InputReader {
private InputStream in;
private byte[] buffer=new byte[1024];
private int curbuf;
private int lenbuf;

public InputReader(InputStream in) {this.in=in;}
  
public int readByte() {
if(lenbuf==-1) throw new InputMismatchException();
if(curbuf>=lenbuf){
curbuf= 0;
try{
lenbuf=in.read(buffer);
}
catch (IOException e) {
throw new InputMismatchException();
}
if(lenbuf<=0)
return -1;
}
return buffer[curbuf++];
}

public boolean isSpaceChar(int c){return !(c>=33&&c<=126);}

private int skip() {int b; while((b = readByte())!=-1&&isSpaceChar(b)); return b;}

public String next() {
int b=skip();
StringBuilder sb=new StringBuilder();
while(!isSpaceChar(b)){
sb.appendCodePoint(b);
b=readByte();
}
return sb.toString();
}
 
public int nextInt() {
int c=readByte();
while (isSpaceChar(c)) c=readByte();
boolean minus=false;
if (c=='-') {
minus=true;
c=readByte();
}
int res=0;
do{
if(c<'0'||c>'9') throw new InputMismatchException();
res=res*10+c-'0';
c=readByte();
}while(!isSpaceChar(c));
return (minus)?-res:res;
}

public long nextLong() {
int c=readByte();
while (isSpaceChar(c)) c=readByte();
boolean minus=false;
if (c=='-') {
minus=true;
c=readByte();
}
long res = 0;
do{
if(c<'0'||c>'9') throw new InputMismatchException();
res=res*10+c-'0';
c=readByte();
}while(!isSpaceChar(c));
return (minus)?-res:res;
}

public double nextDouble(){return Double.parseDouble(next());}

public BigInteger nextBigInteger(){return new BigInteger(next());}

public int[] nextIntArray(int n){
int[] a=new int[n];
for(int i=0;i<n;i++) a[i]=nextInt();
return a;
}
}
}