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