HINHTHANG 27.12.2021

#define task "HINHTHANG"

#include <iostream>
#include <cstdio>

using namespace std;

using ll = long long;
using ld = long double;

constexpr int N = 8e1 + 5;
constexpr int Inf = 1e9 + 7;
int n;
ll S, a[N], b[N];
int dp[N][N];

void Read()
{
    cin >> n >> S;
    ++n;
    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i];
        a[i] += a[i - 1];
    }
    for (int i = 1; i <= n; ++i)
    {
        cin >> b[i];
        b[i] += b[i - 1];
    }
}

void Solve()
{
    fill_n(&dp[0][0], N * N, Inf);

    for (int i = 2; i <= n; ++i)
        for (int j = 2; j <= n; ++j)
        {
            if (a[i] + b[j] <= S)
                dp[i][j] = 1;
            else
                for (int t = i - 1; t; --t)
                    for (int h = j - 1; h; --h)
                        if ((a[i] - a[t - 1]) + (b[j] - b[h - 1]) <= S) // cost <= S
                            dp[i][j] = min(dp[i][j], dp[t][h] + 1);
        }
    cout << (dp[n][n] >= Inf ? -1 : dp[n][n]);
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }
    Read();
    Solve();
}