#include <bits/stdc++.h>
using namespace std;
const long long INF = 1000000007;
const int MAX = 210000;
const int MOD = 1000000007;
long long fac[MAX], finv[MAX], inv[MAX];
void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}
long long COM(int n, int k) {
  if (n < k) return 0;
  if (n < 0 || k < 0) return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int pr[100010];
void uini(int n) {
  for (size_t i = 0; i <= n; i++) {
    pr[i] = i;
  }
}
int parent(int x) {
  if (x == pr[x]) return x;
  return pr[x] = parent(pr[x]);
}
bool unit(int x, int y) {
  int px = parent(x);
  int py = parent(y);
  if (px == py) return false;
  if (px < py) {
    pr[py] = px;
  } else {
    pr[px] = py;
  }
  return true;
}
long long bit[200010];
int max_n = 200000;
int pm = 0;
void add(int x) {
  while (max_n >= x) {
    bit[x]++;
    x += x & -x;
  }
}
void sub(int x) {
  while (max_n >= x) {
    bit[x]--;
    x += x & -x;
  }
}
long long merge(long long* a, int left, int mid, int right) {
  long long n1 = mid - left;
  long long n2 = right - mid;
  vector<int> L(n1 + 1);
  vector<int> R(n2 + 1);
  for (size_t i = 0; i < n1; i++) {
    L[i] = a[left + i];
  }
  for (size_t i = 0; i < n2; i++) {
    R[i] = a[mid + i];
  }
  L[n1] = INF;
  R[n2] = INF;
  long long i = 0;
  long long j = 0;
  long long r = 0;
  for (size_t k = left; k < right; k++) {
    if (L[i] <= R[j]) {
      a[k] = L[i];
      i++;
    } else {
      a[k] = R[j];
      r += n1 - i;
      j++;
    }
  }
  return r;
}
long long merge2(pair<int, char>* a, int left, int mid, int right) {
  long long n1 = mid - left;
  long long n2 = right - mid;
  vector<pair<int, char>> L(n1 + 1);
  vector<pair<int, char>> R(n2 + 1);
  for (size_t i = 0; i < n1; i++) {
    L[i] = a[left + i];
  }
  for (size_t i = 0; i < n2; i++) {
    R[i] = a[mid + i];
  }
  L[n1] = make_pair(INF, ' ');
  R[n2] = make_pair(INF, ' ');
  long long i = 0;
  long long j = 0;
  long long r = 0;
  for (size_t k = left; k < right; k++) {
    if (L[i].first <= R[j].first) {
      a[k] = L[i];
      i++;
    } else {
      a[k] = R[j];
      r += n1 - i;
      j++;
    }
  }
  return r;
}
long long mergeSort2(pair<int, char>* a, int left, int right) {
  long long res = 0;
  if (left + 1 < right) {
    int mid = (left + right) / 2;
    res = mergeSort2(a, left, mid);
    res += mergeSort2(a, mid, right);
    res += merge2(a, left, mid, right);
  }
  return res;
}
long long mergeSort(long long* a, int left, int right) {
  long long res = 0;
  if (left + 1 < right) {
    int mid = (left + right) / 2;
    res = mergeSort(a, left, mid);
    res += mergeSort(a, mid, right);
    res += merge(a, left, mid, right);
  }
  return res;
}
int partition(pair<int, char>* a, int p, int r) {
  pair<int, char> x = a[r];
  int i = p - 1;
  for (size_t j = p; j < r; j++) {
    if (a[j].first <= x.first) {
      i++;
      swap(a[i], a[j]);
    }
  }
  swap(a[i + 1], a[r]);
  return i + 1;
}
void quick(pair<int, char>* a, int p, int r) {
  if (p < r) {
    int q = partition(a, p, r);
    quick(a, p, q - 1);
    quick(a, q + 1, r);
  }
}
long long n;
vector<pair<int, int>> es[100010];
int ci = 0;
long long P[1000010];
struct Node {
  int key;
  int priority;
  Node *parent, *left, *right;
  Node(int key, int priority);
  Node() {}
};
Node NIL;
Node::Node(int key, int priority) : key(key), priority(priority) {
  left = &NIL;
  right = &NIL;
}
Node* root = new Node();
void cenrec(Node* k) {
  if (k->key == NIL.key) return;
  cenrec(k->left);
  cout << " " << k->key;
  cenrec(k->right);
}
void fastrec(Node* k) {
  if (k->key == NIL.key) return;
  cout << " " << k->key;
  fastrec(k->left);
  fastrec(k->right);
}
void insert(Node* v) {
  Node* y = &NIL;
  Node* x = root;
  while (x->key != NIL.key) {
    y = x;
    if (v->key < x->key) {
      x = x->left;
    } else {
      x = x->right;
    }
  }
  v->parent = y;
  if (y->key == NIL.key) {
    root = v;
  } else if (v->key < y->key) {
    y->left = v;
  } else {
    y->right = v;
  }
}
Node* find(Node* k, long long v) {
  if (k->key == NIL.key) return &NIL;
  if (k->key == v) return k;
  if (v < k->key) return find(k->left, v);
  return find(k->right, v);
}
void delp12(Node* x) {
  if (x->key == NIL.key) return;
  Node* l = x->left;
  Node* r = x->right;
  Node* pr = x->parent;
  if (l->key == NIL.key && r->key == NIL.key) {
    if (pr->left == x) {
      pr->left = &NIL;
    } else
      pr->right = &NIL;
  } else if (l->key != NIL.key) {
    if (pr->left == x) {
      pr->left = l;
    } else
      pr->right = l;
    l->parent = pr;
  } else if (r->key != NIL.key) {
    if (pr->left == x) {
      pr->left = r;
    } else
      pr->right = r;
    r->parent = pr;
  }
}
Node* get_next(Node* k) {
  if (k->key == NIL.key) return &NIL;
  Node* res = get_next(k->left);
  if (res->key != NIL.key) return res;
  return k;
}
void del(Node* x) {
  if (x->key == NIL.key) return;
  Node* l = x->left;
  Node* r = x->right;
  Node* pr = x->parent;
  if (l->key != NIL.key && r->key != NIL.key) {
    Node* nex = get_next(r);
    x->key = nex->key;
    delp12(nex);
  } else {
    delp12(x);
  }
}
Node* rightRotate(Node* t) {
  Node* s = t->left;
  t->left = s->right;
  s->right = t;
  return s;
}
Node* leftRotate(Node* t) {
  Node* s = t->right;
  t->right = s->left;
  s->left = t;
  return s;
}
Node* _insert(Node* t, int key, int priority) {
  if (t->key == NIL.key) {
    return new Node(key, priority);
  }
  if (key == t->key) {
    return t;
  }
  if (key < t->key) {
    t->left = _insert(t->left, key, priority);
    if (t->priority < t->left->priority) {
      t = rightRotate(t);
    }
  } else {
    t->right = _insert(t->right, key, priority);
    if (t->priority < t->right->priority) {
      t = leftRotate(t);
    }
  }
  return t;
}
Node* delete1(Node* t, int key);
Node* _delete(Node* t, int key) {
  if (t->left->key == NIL.key && t->right->key == NIL.key) {
    return &NIL;
  } else if (t->left->key == NIL.key) {
    t = leftRotate(t);
  } else if (t->right->key == NIL.key) {
    t = rightRotate(t);
  } else {
    if (t->left->priority > t->right->priority) {
      t = rightRotate(t);
    } else
      t = leftRotate(t);
  }
  return delete1(t, key);
}
Node* delete1(Node* t, int key) {
  if (t->key == NIL.key) {
    return &NIL;
  }
  if (key < t->key) {
    t->left = delete1(t->left, key);
  } else if (key > t->key) {
    t->right = delete1(t->right, key);
  } else
    return _delete(t, key);
  return t;
}
int H;
int left(int i) { return i * 2 + 1; }
int right(int i) { return i * 2 + 2; }
long long heap[2000010];
void maxHeapify(int i) {
  int l = left(i);
  int r = right(i);
  int largest = 0;
  if (l < H && heap[l] > heap[i])
    largest = l;
  else
    largest = i;
  if (r < H && heap[r] > heap[largest]) largest = r;
  if (largest != i) {
    swap(heap[i], heap[largest]);
    maxHeapify(largest);
  }
}
int pare(int i) { return (i - 1) / 2; }
void raise(int i) {
  int l = pare(i);
  if (l < 0) return;
  if (heap[l] < heap[i]) {
    swap(heap[i], heap[l]);
    raise(l);
  }
}
void minHeapify(int i) {
  int l = left(i);
  int r = right(i);
  int minimam = 0;
  if (l < H && heap[l] < heap[i])
    minimam = l;
  else
    minimam = i;
  if (r < H && heap[r] < heap[minimam]) minimam = r;
  if (minimam != i) {
    swap(heap[i], heap[minimam]);
    minHeapify(minimam);
  }
}
void buildMaxHeap() {
  for (int i = H / 2; i >= 0; i--) {
    maxHeapify(i);
  }
}
long long lcs(string s1, string s2) {
  long long dp[1010][1010];
  memset(dp, 0, sizeof(dp));
  int s1l = s1.size();
  int s2l = s2.size();
  for (size_t i = 1; i <= s1l; i++) {
    for (size_t j = 1; j <= s2l; j++) {
      if (s1[i - 1] == s2[j - 1]) {
        dp[i][j] = dp[i - 1][j - 1] + 1;
      } else {
        dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
      }
    }
  }
  return dp[s1l][s2l];
}
struct edge {
  long long to, cap, rev;
  edge(int to, int cap, int rev) : to(to), cap(cap), rev(rev) {}
};
struct edge2 {
  long long to, cost;
  edge2(int to, int cost) : to(to), cost(cost) {}
};
vector<edge> ed[100010];
void addedge(int f, int t, int c) {
  ed[f].push_back(edge(t, c, ed[t].size()));
  ed[t].push_back(edge(f, 0, ed[f].size() - 1));
}
vector<int> es2[100010];
long long d[100010];
void dij(int x) {
  d[x] = 0;
  priority_queue<pair<long long, long long>, vector<pair<long long, long long>>,
                 greater<pair<long long, long long>>>
      q;
  q.push(pair<long long, long long>(0, x));
  while (!q.empty()) {
    pair<long long, long long> p = q.top();
    q.pop();
    if (d[p.second] < p.first) continue;
    for (auto v : ed[p.second]) {
      if (d[v.to] > d[p.second] + v.cap) {
        d[v.to] = d[p.second] + v.cap;
        q.push(pair<long long, long long>(d[v.to], v.to));
      }
    }
  }
}
int tb[5][5];
int ex[5][5];
pair<int, int> mdv[16];
int check() {
  int p = 1;
  int wc = 0;
  for (size_t i = 0; i < 4; i++) {
    for (size_t j = 0; j < 4; j++) {
      if (tb[i][j] != p) wc++;
      p++;
      p %= 16;
    }
  }
  return wc;
}
int lim = 45;
int md = 0;
int dx[] = {-1, 0, 1, 0};
int dy[] = {0, -1, 0, 1};
int res = INF;
int calcMd(int x, int y, int v) {
  return abs(mdv[v].first - x) + abs(mdv[v].second - y);
}
void rec(int x, int y, int deep) {
  if (deep >= res) return;
  if (deep > lim) return;
  if (check() == 0) {
    res = deep;
    return;
  }
  for (size_t i = 0; i < 4; i++) {
    if (deep >= res) return;
    int tx = x + dx[i], ty = y + dy[i];
    if (tx < 0 || ty < 0 || tx >= 4 || ty >= 4) continue;
    int bef = calcMd(tx, ty, tb[tx][ty]);
    swap(tb[tx][ty], tb[x][y]);
    int af = calcMd(x, y, tb[x][y]);
    if (deep + md - bef + af <= lim) {
      md -= bef;
      md += af;
      rec(tx, ty, deep + 1);
      md += bef;
      md -= af;
      for (size_t j = 0; j < 4; j++) {
        for (size_t k = 0; k < 4; k++) {
          cout << " " << tb[j][k];
        }
        cout << endl;
      }
    }
    swap(tb[tx][ty], tb[x][y]);
  }
}
int cm[100010];
bool vis[100010];
int rec(int x) {
  vis[x] = true;
  int cont = 0;
  for (auto v : es2[x]) {
    if (vis[v]) continue;
    int tr = rec(v);
    if (tr < 0) return -1;
    cont += tr;
  }
  if (cont > 1) return -1;
  if (cm[x]) cont = 1;
  return cont;
}
int sp = 0;
int maxdep = 0;
void search(int x, int deep) {
  vis[x] = true;
  if (maxdep < deep && cm[x]) {
    sp = x;
  }
  for (auto v : es2[x]) {
    if (vis[v]) continue;
    search(v, deep + 1);
  }
}
long long memo[110][100010];
long long a[3010];
int k;
long long recg(int index, int rem) {
  if (~memo[index][rem]) return memo[index][rem];
  if (index >= n) {
    if (rem == 0)
      return 1;
    else
      return 0;
  }
  long long& res = memo[index][rem];
  bool exists = false;
  if (~memo[index][rem - 1]) {
    res = memo[index][rem - 1];
    exists = true;
  } else
    res = 0;
  int st = !exists ? 0 : rem;
  for (int i = st; i <= rem; i++) {
    long long p = recg(index + 1, i);
    if (p == 0) break;
    res += p;
    res %= INF;
  }
  if (rem - a[index] > 0) {
    long long sub = 0;
    if (~memo[index][rem - a[index]]) {
      sub = memo[index][rem - a[index] - 1];
    } else {
      sub = recg(index, rem - a[index] - 1);
    }
    long long tmpval = (res + INF - sub) % INF;
    return tmpval;
  }
  return res %= INF;
}
void solv() {
  cin >> n >> k;
  for (size_t i = 0; i < n; i++) {
    cin >> a[i];
  }
  memset(memo, -1, sizeof(memo));
  long long r = 0;
  for (int i = max(0LL, k - a[0]); i <= k; i++) {
    r += recg(1, i);
    r %= INF;
  }
  cout << r << endl;
}
int main() {
  solv();
  return 0;
}
