#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, cnt = 0;
  string s;
  cin >> n >> s;
  for (int i = 0; i < n; i += 2) {
    if (s[i] == s[i + 1]) {
      s[i] = (s[i] == 'a' ? 'b' : 'a');
      cnt++;
    }
  }
  cout << cnt << '\n' << s << '\n';
}
