/*
DP问题
T分钱,可以由最少的硬币数组成
*/
// include file
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <ctime>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <bitset>
#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <list>
#include <functional>
using namespace std;
// typedef
typedef __int64 LL;
//
#define read freopen("in.txt","r",stdin)
#define write freopen("out.txt","w",stdout)
#define Z(a,b) ((a)<<(b))
#define Y(a,b) ((a)>>(b))
const double eps = 1e-6;
const double INFf = 1e100;
const int INFi = 1000000000;
const LL INFll = (LL)1<<62;
const double Pi = acos(-1.0);
template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T TMAX(T x,T y)
{
if(x>y) return x;
return y;
}
template<class T> inline T TMIN(T x,T y)
{
if(x<y) return x;
return y;
}
template<class T> inline T MMAX(T x,T y,T z)
{
return TMAX(TMAX(x,y),z);
}
template<class T> inline T MMIN(T x,T y,T z)
{
return TMIN(TMIN(x,y),z);
}
template<class T> inline void SWAP(T &x,T &y)
{
T t = x;
x = y;
y = t;
}
// code begin
int N,T;
struct node
{
int v;
int c;
};
node pac[110];
int DP[14400];
int DP2[14400];
int main()
{
read;
write;
while(scanf("%d %d",&N,&T)==2)
{
for(int i=0;i<N;i++)
{
scanf("%d",&pac[i].v);
}
for(int i=0;i<N;i++)
{
scanf("%d",&pac[i].c);
}
int up = 14400;
fill(DP,DP+up,INFi);
DP[0] = 0;
for(int i=0;i<N;i++)
{
//
int begin = 1;
while(begin<pac[i].c)
{
// zeroone
for(int j=up-1;j>=0;j--)
{
if(j-pac[i].v*begin<0) break;
DP[j] = TMIN(DP[j],DP[j-pac[i].v*begin]+begin);
}
pac[i].c-=begin;
begin*=2;
}
//zeroone
for(int j=up-1;j>=0;j--)
{
if(j-pac[i].v*pac[i].c<0) break;
DP[j] = TMIN(DP[j],DP[j-pac[i].v*pac[i].c]+pac[i].c);
}
}
fill(DP2,DP2+14400,INFi);
DP2[0] = 0;
for(int i=0;i<N;i++)
{
for(int j=0;j<14400;j++)
{
if(j+pac[i].v>=14400) break;
DP2[j+pac[i].v] = TMIN(DP2[j+pac[i].v],DP2[j]+1);
}
}
int ans = INFi;
for(int i=T;i<up;i++)
{
if(DP[i]+DP2[i-T]<ans)
ans=DP[i]+DP2[i-T];
}
if(ans!=INFi) printf("%d\n",ans);
else printf("-1\n");
}
return 0;
}