#include <iostream>
#include <vector>

int longestPlayground(const std::vector<int>& arr) {
    if (arr.empty()) {
        return 0;
    }

    int maxLen = 1;
    int currentLen = 1;
    for (size_t i = 1; i < arr.size(); ++i) {
        if (arr[i] == arr[i - 1]) {
            currentLen++;
        } else {
            maxLen = std::max(maxLen, currentLen);
            currentLen = 1;
        }
    }
    maxLen = std::max(maxLen, currentLen); 

    return maxLen;
}

int main() {
    std::vector<int> arr = {1, 3, 3, 7, 9, 9, 9, 9, 11, 11, 12, 14};
    int result = longestPlayground(arr);
    std::cout << result << std::endl;  // Output: 4
    return 0;
}