#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

int main() {
	int N; long long M;
	while(~scanf("%d%lld", &N, &M)) {
		vector<int> A(N);
		for(int i = 0; i < N; ++ i)
			scanf("%d", &A[i]);
		long long sum = 0;
		for(int i = 0; i < N; ++ i) {
			long long K;
			scanf("%lld", &K);
			sum += K * A[i];
		}
		if(sum < M) {
			puts("-1");
			continue;
		}
		int X = A[N - 1];
		long long Y = sum - M;
		long long quot = Y / X;
		int rem = Y % X;
		long long ans = INFL;
		vi dp(X, INF);
		dp[0] = 0;
		rep(i, X) {
			if(i > quot) break;
			int mid = N - 1;
			rep(j, X) {
				int x = dp[j];
				if(x == INF) continue;
				if(j == rem)
					amin(ans, x + quot);
				for(; mid > 0 && j + A[mid - 1] >= X; -- mid)
					;
				rep(k, mid)
					amin(dp[j + A[k]], x + 1);
				reu(k, mid, N - 1)
					amin(dp[j + A[k] - X], x);
			}
		}
		if(ans == INFL)
			puts("-1");
		else
			printf("%lld\n", ans);
	}
	return 0;
}