#include <bits/stdc++.h>
using namespace std;
int main() {
  int k, count = 0;
  cin >> k;
  string s;
  cin >> s;
  int i;
  for (i = 0; i < k; i++) {
    if (i % 2 == 0) {
      if (s[i] == 'a' && s[i + 1] == 'a') {
        s[i] = 'b';
        count++;
      } else if (s[i] == 'b' && s[i + 1] == 'b') {
        s[i] = 'a';
        count++;
      }
    }
  }
  cout << count << "\n";
  cout << s << "\n";
  return 0;
}
