#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int count = 0, n;
  string str;
  cin >> n;
  cin >> str;
  for (int i = 0; i < n; i += 2) {
    if ((str[i] == 'a' && str[i + 1] == 'b') ||
        (str[i] == 'b' && str[i + 1] == 'a')) {
      continue;
    } else {
      if (str[i] == 'a')
        str[i] = 'b';
      else if (str[i] == 'b')
        str[i] = 'a';
      count++;
    }
  }
  cout << count << endl;
  cout << str << endl;
  return 0;
}
