#include <bits/stdc++.h>
using namespace std;
int n;
string s;
int main(void) {
  std::ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  cin >> s;
  int len = s.size();
  int ans = 0;
  for (int i = 0; i < len; i += 2) {
    if (s[i] == 'a' && s[i + 1] == 'a') {
      ans++;
      s[i + 1] = 'b';
    } else if (s[i] == 'b' && s[i + 1] == 'b') {
      ans++;
      s[i] = 'a';
    }
  }
  cout << ans << endl;
  cout << s << endl;
  return 0;
}
