#include <bits/stdc++.h>

using i64 = long long;
using u64 = unsigned long long;
using u32 = unsigned;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int n, k;
    std::cin >> n >> k;
    
    std::vector<int> a(n);
    for (int i = 0; i < n; i++) {
        std::cin >> a[i];
    }
    
    if (std::count(a.begin(), a.end(), 0) >= k) {
        std::cout << 0 << "\n";
        return 0;
    }
    
    std::vector<int> dp(n + 1, -1);
    dp[0] = 0;
    int mx1 = -1;
    std::deque<int> q {0};
    for (int i = 1, j = -1, k = 0; i <= n; i++) {
        if (a[i - 1] == 1) {
            while (j < i - 1) {
                j++;
                mx1 = std::max(mx1, dp[j]);
            }
        }
        if (a[i - 1] == 0) {
            k = i;
            while (!q.empty() && q[0] < k) {
                q.pop_front();
            }
        }
        dp[i] = mx1;
        if (!q.empty()) {
            dp[i] = std::max(dp[i], dp[q[0]]);
        }
        if (dp[i] >= 0) {
            dp[i]++;
        }
        while (!q.empty() && dp[i] >= dp[q.back()]) {
            q.pop_back();
        }
        q.push_back(i);
    }
    
    if (k <= dp[n]) {
        std::cout << 1 << "\n";
        return 0;
    }
    
    if (std::count(a.begin(), a.end(), 2) > 0) {
        std::cout << 2 << "\n";
        return 0;
    }
    
    int lst = -1;
    int res = 0;
    for (int i = 0; i < n; i++) {
        if (a[i] <= 1) {
            if (a[i] != lst) {
                res++;
            }
            lst = a[i];
        }
    }
    if (k >= res) {
        std::cout << 2 << "\n";
        return 0;
    }
    
    std::cout << 3 << "\n";
    
    return 0;
}