#include <bits/stdc++.h>
using namespace std;
char s[200005];
int main(int argc, char *argv[]) {
  int n;
  cin >> n;
  cin >> s;
  int ans = 0;
  for (int i = 1; i < n; i += 2) {
    if (s[i - 1] == s[i]) {
      ans++;
      if (s[i] == 'a')
        s[i] = 'b';
      else
        s[i] = 'a';
    }
  }
  cout << ans << endl;
  cout << s;
}
