#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int>P;
typedef vector<int>VI;
#define rep(i,n) for(int i=0;i<(n);i++)
#define pb push_back
#define all(v) (v).begin(),(v).end()
#define maxv(a,b) (a)=max((a),(b))
#define minv(a,b) (a)=min((a),(b))
#define int long long
const int INF=LLONG_MAX/100;
int N,M,A[500],K[500];

int dp[250010];


signed main(){
    cin>>N>>M;
    rep(i,N)cin>>A[i];
    rep(i,N)cin>>K[i];

    int sum=0,ma=0;
    rep(i,N)sum+=A[i]*K[i];
    sum-=M;
    if(sum<0){
        cout<<"-1"<<endl;
        return 0;
    }

    rep(i,N)maxv(ma,A[i]);

    rep(i,ma*ma+1)dp[i]=INF;
    dp[0]=0;
    rep(i,N){
        rep(j,ma*ma+1)if(j-A[i]>=0)minv(dp[j],dp[j-A[i]]+1);
    }

    int ans=0;
    if(sum>ma*ma){
        int m=sum-ma*ma;
        ans+=(m+ma-1)/ma;
        sum-=(m+ma-1)/ma*ma;
    }
    if(dp[sum]==INF)cout<<"-1"<<endl;
    else cout<<ans+dp[sum]<<endl;
    return 0;
}