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