#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, ans = 0;
  cin >> n;
  string s, t;
  cin >> s;
  t = s;
  for (int i = 0; i < n - 1; i += 2) {
    if (s[i] == s[i + 1] && s[i] == 'a') {
      t[i] = 'b';
      ans++;
    } else if (s[i] == s[i + 1]) {
      t[i] = 'a';
      ans++;
    }
  }
  cout << ans << endl;
  cout << t;
}
