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