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