#include <bits/stdc++.h>

using namespace std;


#define ll long long
#define flt double
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define rep(i, n) for(int i = 0; i < n; i += 1)


const ll inf = 1e18;
mt19937 rnd(234);


int32_t main() {
    if (1) {
        ios::sync_with_stdio(0);
        cin.tie(0);
        cout.tie(0);
    }
    int n, B;
    cin >> n >> B;
    vector<vector<pair<int, int>>> starts(n);
    vector<int> a(n);
    int t = 0;
    rep(i, n) cin >> a[i];
    rep(i, n) {
        if (a[i] == -1) {
            t += 1;
        } else {
            starts[a[i] - 1].push_back(make_pair(t, i));
        }
    }
    vector<int> ends(n, -1);
    for (int q = 0; q < n; q += 1) {
        stack<int> s;
        int j = 0;
        int t = 0;
        while (j < (int)starts[q].size() or !s.empty()) {
            if (s.empty()) {
                t = starts[q][j].first;
            }
            while (j < (int)starts[q].size() and starts[q][j].first == t) {
                s.push(starts[q][j].second);
                j++;
            }
            if (!s.empty()) {
                int k = s.top();
                ends[k] = t;
                s.pop();
            }
        }
    }
    set<pair<int, int>> st;
    vector<int> result;
    t = 0;
    for (int i = 0; i < n; i += 1) {
        if (ends[i] == -1) {
            t += 1;
            while (!st.empty() and st.begin()->first < t) {
                result.push_back(st.begin()->second);
                st.erase(st.begin());
            }
            continue;
        }
        st.insert(make_pair(ends[i], i));
        if ((int)st.size() > B) {
            auto it = prev(st.end());
            st.erase(it);
        }
    }
    while (!st.empty()) {
        result.push_back(st.begin()->second);
        st.erase(st.begin());
    }
    sort(all(result));
    cout << (int)result.size() << "\n";
    for (auto x : result) {
        cout << x + 1 << " ";
    }
    cout << "\n";
    return 0;
}

/*
14 5
1 1 1 2 2 2 -1 1 -1 1 -1 1 -1 1

14 4
1 1 1 2 2 2 -1 1 -1 1 -1 1 -1 1

*/