#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  cin >> n;
  string s;
  cin >> s;
  long long count = 0;
  for (long long i = 0; i < n; i += 2) {
    if (s[i] == s[i + 1]) {
      s[i] = ((s[i + 1] == 'a') ? 'b' : 'a');
      count++;
    }
  }
  cout << count << endl;
  cout << s << endl;
}
