#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  char str[200010];
  cin >> n;
  cin >> str;
  int a = 0;
  int b = 0;
  int res = 0;
  for (int i = 0; i < n; i += 2) {
    if (str[i] == 'a' && str[i + 1] == 'a') {
      str[i + 1] = 'b';
      res++;
    } else if (str[i] == 'b' && str[i + 1] == 'b') {
      str[i] = 'a';
      res++;
    }
  }
  cout << res << endl;
  cout << str << endl;
  return 0;
}
