#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string arr;
  cin >> arr;
  int tot = 0, cur = 0;
  for (int i = 0; i < arr.size(); i += 2) {
    if (i + 1 == arr.size()) break;
    cur = 0;
    for (int j = i; j <= i + 1; j++) {
      if (arr[j] == 'b')
        cur++;
      else
        cur--;
    }
    if (cur != 0) {
      tot++;
      if (arr[i] == 'a')
        arr[i] = 'b';
      else
        arr[i] = 'a';
    }
  }
  cout << tot << '\n';
  cout << arr;
  return 0;
}
