#include <bits/stdc++.h>
using namespace std;
 
const int MAXH = 500000;
 
vector<int> P[1 + MAXH];
 
int main()
{
    int k, n;
    cin >> n >> k;
    for (int i = 0; i < n; ++i) {
        int h;
        cin >> h;
        P[h].push_back(i);
    }
    int b = 0;
    for (int h = 1; h <= MAXH; ++h) {
        for (int i = 0, j = 0; j < (int)P[h].size(); ++j) {
            int a = P[h][j] - P[h][i] + 1;
            int c = j - i + 1;
            while (a - c > k) {
                ++i;
                a = P[h][j] - P[h][i] + 1;
                c = j - i + 1;
            }
            b = max(b, c);
        }
    }
    cout << b << endl;
    return 0;
}

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