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