9 13
6 14 19 5 -5 6 -10 20 8
 8 9
6 -1 5 -5 -8 -7 -8 -7
 10 7
-9 3 -4 -22 4 -17 0 -14 3 -2
 6 2
-2 3 0 -2 0 0
 5 10
-8 -24 0 -22 12
 5 13756
-2 -9 -10 0 10
 7 3
1 -3 0 3 -1 0 2
 9 9
-3 2 0 -2 -7 -1 0 5 3
 2 3
2 0
 19 78701
1 0 -1 0 -1 -1 0 1 0 -1 1 1 -1 1 0 0 -1 0 0
 5 4
-1 0 0 1 -1
 6 4
-1 0 2 -4 0 5
 20 23036
-1 1 -1 -1 -1 -1 1 -1 -1 0 0 1 1 0 0 1 0 0 -1 -1
 5 4
-1 0 -3 0 3
 12 82016
1 -2 -1 -1 -2 -1 0 -2 -1 1 -2 2
 7 4
-6 0 2 -3 0 4 0
 4 4
2 2 0 1
 6 1
-3 0 0 0 -2 3
 8 26
-4 9 -14 -11 0 7 23 -15
 20 23079
0 1 1 -1 1 0 -1 -1 0 0 1 -1 1 1 1 0 0 1 0 1
 1 1
1
 7 8555
-2 -3 -2 3 0 -2 0
 4 100
-100 0 -50 100
 3 14
12 12 -8
 1 1
2
 10 23
9 7 14 16 -13 -22 24 -3 -12 14
 8 11
12 -12 -9 3 -22 -21 1 3
 19 49926
-2 0 2 0 0 -2 2 -1 -1 0 0 0 1 0 1 1 -2 2 2
 16 76798
-1 11 -7 -4 0 -11 -12 3 0 -7 6 -4 8 6 5 -10
 9 5
-2 0 3 -4 0 4 -3 -2 0

-1
 -1
 1
 1
 1
 1
 -1
 2
 0
 1
 1
 -1
 1
 1
 1
 1
 -1
 1
 -1
 0
 0
 1
 1
 -1
 -1
 -1
 -1
 1
 1
 1

#include <bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

#define int long long


typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

#define fs first
#define sc second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define pb push_back
#define MP make_pair
#define sz(x) (int)x.size()
#define fastio ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)

const int INF = 1e9 + 123;
signed main() {
    fastio;

    int n, d;
    cin >> n >> d;
    vector<int> a(n);
    for (int i = 0; i < n; i++)
        cin >> a[i];
    int bal = 0;
    int ans = 0;
    int mx = 0;
    for (int i = 0; i < n; i++) {
        bal += a[i];
        mx = max(mx, bal);
        if (bal > d) {
            cout << -1;
            return 0;
        }
        if (a[i] == 0) {
            if (bal >= 0)
                continue;
            if (mx + abs(bal) > d || ans == 0)
                ans++;
            mx = 0;
            bal = 0;
        }
    }
    cout << ans << '\n';
}