#include <bits/stdc++.h>
using namespace std;
int main() {
  int q;
  cin >> q;
  string w;
  cin >> w;
  int answer = 0;
  for (int k = 1; k < q; k += 2) {
    if (w[k] == w[k - 1]) {
      if (w[k] == 'a')
        w[k] = 'b';
      else
        w[k] = 'a';
      answer++;
    }
  }
  cout << answer << endl;
  cout << w;
}
