func_code_string: #include <bits/stdc++.h>   using namespace std;   int a[5010], n, s = 0, i;   int main() {     cin >> n >> i;     for (i = 0; i < n; i++) cin >> a[i];     sort(a, a + n);     for (i = 0; i < n; i++) s += a[i] != a[(i + n / 2) % n];     cout << s << endl;     for (i = 0; i < n; i++) cout << a[i] <<     << a[(i + n / 2) % n] << endl;   }   