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>
#define ll          long long
#define pb          push_back
#define c(P)        cout<<P<<"\n"
#define pii         pair<ll,ll>
#define mi          map<ll,ll>
#define mii         map<pii,ll>
#define F           first
#define S           second
#define sz(a)       (ll)(a.size())
#define cr(P)       cout<<P<<"\n";return;
#define mem(a,val)  memset(a,val,sizeof(a))
#define fr(i,x,n)   for(ll i=x;i<n;i++)
#define frr(i,x,n)  for(ll i=n-1;i>=x;i--)
using namespace std;


const ll N   =  500005;
const ll mod = 1e9 + 7;



void solve(){

  ll x=0,y=0,c=0,ans=0;
  ll n,m,k;
  cin>>n >> k;
  ll a[n];
  ll pre[n] ={0};
  for (ll i = 0; i < n; ++i){
    if(i>0)
     pre[i]  = pre[i-1];
      cin >> a[i];
      c+=a[i];
      pre[i]  = max(pre[i],c);
  }

  for (ll i = 0; i < n; ++i){
    c+=a[i];

     if(c>k){
        cr(-1);
     }

     if(a[i] == 0 and c<0){
      x = -c;
      y = 1e15;
      ans++;
      ll p = 0;
      while(x<=y){
        ll mid = (x+y+1)/2;
        
        m = mid + c;
        ll flag = 1;

        if(pre[n-1]+m>k){
            flag = 0;
        }

        if(flag){
      
            p = mid+c;
            x  =mid+1;
        }
        else {
            y = mid -1;
        }

      }
      
      c+=p;
      }

     }
     c(ans);


  
 
}

signed main(){
     
  ios_base::sync_with_stdio(false);   
  cin.tie(NULL);
  //int T;cin >> T;while (T--)
  solve();
  return 0;
}
