#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 10;
const int mod = 998244353;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(10);
  cout << fixed;
  int n;
  string x;
  cin >> n >> x;
  int ans = 0;
  for (int i = 0; i < n; i += 2) {
    if (x[i + 0] == x[i + 1]) {
      if (x[i] == 'a')
        x[i] = 'b';
      else
        x[i] = 'a';
      ans++;
    }
  }
  cout << ans << endl << x << endl;
}
