[PCCA 2020 pG]

#include <bits/stdc++.h>
using namespace std;

#define int long long

#define fastIO() ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define X first
#define Y second

int32_t main() {
    fastIO();

    int n, k, ans = 0;
    cin >> n >> k;

    vector<int> a(n);
    vector<pair<int, int>> jump(n);
    for (auto &x : a) cin >> x;

    for (int i = n-1; i >= 0; --i) {
        if (i + a[i] >= n) {
            jump[i].X = n;
            jump[i].Y = 1;
        }
        else {
            jump[i].X = jump[i + a[i]].X;
            jump[i].Y = jump[i + a[i]].Y + 1;
        }
        ans += (jump[i].Y <= k and jump[i].X == n);
    }

    cout << ans << "\n";

    return 0;
}