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