#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long int n;
  cin >> n;
  string s;
  cin >> s;
  long long int ans = 0;
  for (long long int i = 0; i < n; i = i + 2) {
    if (s[i] == s[i + 1]) {
      ans++;
      if (s[i] == 'a')
        s[i] = 'b';
      else if (s[i] == 'b')
        s[i] = 'a';
    }
  }
  cout << ans << '\n';
  cout << s << '\n';
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int t;
  t = 1;
  while (t--) {
    solve();
  }
}
