#include <bits/stdc++.h>
using namespace std;
int main(int argc, char *argv[]) {
  int n;
  string str;
  string ans = "";
  while (cin >> n) {
    cin >> str;
    int now = 0;
    int vis[26];
    ans = "";
    while (now < str.length()) {
      char tmp = str[now];
      int diff = 0;
      memset(vis, 0, sizeof vis);
      int flag = 0;
      for (int i = now + 1; i < str.length(); i++) {
        if (str[i] != tmp) {
          flag = 1;
          ans.push_back(tmp);
          ans.push_back(str[i]);
          now = i + 1;
          break;
        }
        if (!vis[str[i] - 'a']) {
          diff++;
          if (diff > 2) {
            flag = 1;
            now = now + 1;
            break;
          }
        }
      }
      if (flag == 0) {
        break;
      }
    }
    cout << str.length() - ans.length() << endl;
    cout << ans << endl;
  }
}
