#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, ans = 0;
  cin >> n;
  char a[200010];
  cin >> a;
  for (int i = 1; i < n; i += 2) {
    if (a[i - 1] != a[i])
      continue;
    else if (a[i] == 'a') {
      a[i] = 'b';
      ans++;
    } else {
      a[i] = 'a';
      ans++;
    }
  }
  cout << ans << endl << a;
}
