#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, counta, countb, changes;
  counta = 0;
  countb = 0;
  string inp;
  cin >> n;
  cin >> inp;
  for (int j = 0; j < inp.length() - 1; j = j + 2) {
    if (inp[j] == 'a' && inp[j + 1] == 'a')
      counta++;
    else if (inp[j] == 'b' && inp[j + 1] == 'b')
      counta++;
  }
  cout << counta << endl;
  for (int j = 0; j < inp.length() - 1; j = j + 2) {
    if (inp[j] == 'a' && inp[j + 1] == 'a')
      cout << "ba";
    else if (inp[j] == 'b' && inp[j + 1] == 'b')
      cout << "ab";
    else
      cout << inp[j] << inp[j + 1];
  }
  cout << endl;
  return 0;
}
