#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, s, p, k, m, t, x, y, z, ans, res;
  string a;
  cin >> n >> a;
  ans = 0;
  for (int i = 0; i < n; i += 2) {
    if (a[i] == a[i + 1]) {
      if (a[i] == 'a')
        a[i] = 'b';
      else
        a[i] = 'a';
      ans++;
    }
  }
  cout << ans << endl << a << endl;
  return 0;
}
