#include <bits/stdc++.h>
using namespace std;
string s;
int n;
int main() {
  cin >> n;
  cin >> s;
  int ans = 0;
  for (int i = 1; i < n; i += 2) {
    if (s[i] == s[i - 1]) {
      ans++;
      if (s[i] == 'b')
        s[i] = 'a';
      else
        s[i] = 'b';
    }
  }
  printf("%d\n", ans);
  for (int i = 0; i < n; i++) printf("%c", s[i]);
  return 0;
}
