#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  long long int n;
  cin >> n;
  cin >> s;
  int cnt = 0;
  for (int i = 0; i < n; i += 2) {
    if (s[i] == 'a' && s[i + 1] != 'b') {
      s[i + 1] = 'b';
      cnt++;
    }
    if (s[i] == 'b' && s[i + 1] != 'a') {
      s[i + 1] = 'a';
      cnt++;
    }
  }
  cout << cnt << endl;
  cout << s << endl;
  return 0;
}
