string_comparison

#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
#include <sstream>
using namespace std;
bool cmp(istringstream &s) {
    vector<string> a;
    string word;
    while (s >> word) {
        a.push_back(word);
    }
    if (a.empty()) {
        cout << "Yes\n";
        exit(0);
    }
    int n = a.size();
    if (n % 2 != 0) {
        return false;
    }
    for (int i = 0; i < n/2; ++i) {
        if (a[i] != a[n/2 + i]) {
            return false;
        }
    }
    return true;
}
int main() {
    string line;
    while (getline(cin, line)) {
        istringstream s(line);
        if (!cmp(s)) {
            cout << "No\n";
            exit(0);
        }
    }
    return 0;
}