#include <bits/stdc++.h>
using namespace std;
int main() {
  int q, i, l = 0;
  char s[200001];
  cin >> q >> s;
  for (i = 0; i < q; i += 2) {
    if (s[i] == s[i + 1]) l++;
    if (s[i] == 'a')
      s[i + 1] = 'b';
    else
      s[i + 1] = 'a';
  }
  cout << l << "\n" << s;
  return 0;
}
