#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, cnt = 0;
  cin >> n;
  string s, S = "";
  cin >> s;
  for (int i = 0; i < n - 1; i += 2) {
    if (s[i] == s[i + 1]) {
      cnt++;
      if (s[i] == 'a') {
        S += "b";
        S += "a";
      } else {
        S += "a";
        S += "b";
      }
    } else {
      S += s[i];
      S += s[i + 1];
    }
  }
  cout << cnt << "\n";
  cout << S;
  return 0;
}
