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