#include<bits/stdc++.h>
using namespace std;
int main(){
    int coin,amount;
    vector<int> coins;
    while(cin>>coin){
        coins.push_back(coin);
        if(cin.peek=='\n') break;
    }
    cin>>amount;
    vector<int> dp(amount+1,INT_MAX);
    for(int i=0;i<=amount;i++){
        for(int coin:coins){
            if(i-coin>=0 && dp[i-coin] != INT_MAX){
                dp[i]=min(dp[i],dp[i-coin]+1);
            }
        }
    }
    if(dp[amount]==INT_MAX){
        cout<< -1;
    }else{
        cout<<dp[amount];
    }
    return 0;
}