#include <iostream>
#include <math.h>
#include <vector>
#include <algorithm>
#include <string>
#include <unordered_map>


const int p = 11;


long long segment_hash(int l, int r, std::vector<long long> &hash, std::vector<long long> &pow_p) {
    return hash[r] - hash[l - 1] * pow_p[r - l + 1];
}


int max_palindrom_suffix(std::vector<long long> &hash, std::vector<long long> &rev_hash, std::vector<long long> &pow_p) {
    for (int M = hash.size() - 1; M >= 1; M--) {
        long long hash1 = segment_hash(hash.size() - M, hash.size() - 1, hash, pow_p);
        long long hash2 = segment_hash(1, M, rev_hash, pow_p);
        if (hash1 == hash2)
            return M;
    }
}


int main() {
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    int n;
    std::cin >> n;
    std::vector<long long> pow_p(n + 1, 1);
    for (int i = 1; i < n + 1; i++) {
        pow_p[i] = pow_p[i - 1] * p;
    }
    std::string s;
    int x;
    for (int i = 0; i < n; i++) {
        std::cin >> x;
        s += '0' + x;
    }
    std::vector<long long> hash(n + 1);
    std::vector<long long> rev_hash(n + 1);
    for (int i = 1; i < n + 1; i++) {
        hash[i] = hash[i - 1] * p + (s[i - 1] - '0');
        rev_hash[i] = rev_hash[i - 1] * p + (s[n - i] - '0');
    }
    int length = max_palindrom_suffix(hash, rev_hash, pow_p);
    //std::cout << length;
    //std::cout << segment_hash(1, 2, hash, pow_p);
    //std::cout << segment_hash(3, 4, hash, pow_p);
    std::cout << n - length << "\n";
    for (int i = n - length - 1; i >= 0; i--) {
        std::cout << s[i] << ' ';
    }
    return 0;
}