import java.util.Scanner;
public class Package01_CostMBuyN {
public static void main(String[] args){
Scanner in = new Scanner(System.in);
int n = in.nextInt();
int[] ps = new int[n];
for(int i = 0; i < n; i++){
ps[i] = in.nextInt();
}
int m = in.nextInt();
int res = solution(ps, m ,n);
System.out.println(res);
}
public static int solution(int[] ps, int m, int n){
int res = -1;
int[][] dp = new int[n+1][m+1];
for(int j = 0; j < m+1; j ++){
dp[0][j] = -1;
}
for(int i = 0; i < n+1; i++){
dp[i][0] = 0;
}
for(int l = 1; l <= n; l++){
for(int r = 1; r <= m; r++){
int min = Integer.MAX_VALUE;
dp[l][r] = -1;
for(int c = 0; c <= r ; c ++){
int num = 0;
if((r - c)%ps[l-1] != 0){
continue;
}
int cur = (r - c)/ps[l-1];
if(dp[l-1][c] == -1){
continue;
}else{
num = dp[l - 1][c] + cur;
}
if(num < min ){
min = num;
dp[l][r] = min;
}
}
}
}
return dp[n][m];
}
}