#include <bits/stdc++.h>
using namespace std;
void CyBerForCe() {
  long long n;
  cin >> n;
  string s;
  cin >> s;
  long long cnt = 0;
  for (long long i = 0; i < n; i += 2) {
    if (s[i] == s[i + 1]) {
      cnt++;
      if (s[i + 1] == 'b')
        s[i] = 'a';
      else
        s[i] = 'b';
    }
  }
  cout << cnt << "\n" << s;
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  CyBerForCe();
  return 0;
}
