#include <bits/stdc++.h>
using namespace std;
long long n;
string s;
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  cin >> n >> s;
  long long ans = 0;
  for (long long i = 1; i < n; i += 2) {
    if (s[i] == s[i - 1]) {
      ans++;
      if (s[i] == 'a')
        s[i] = 'b';
      else
        s[i] = 'a';
    }
  }
  cout << ans << "\n";
  cout << s;
  return 0;
}
