#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  string x;
  cin >> x;
  int cnt = 0, a = 0;
  for (int i = 0; i < n; i += 2) {
    if (x[i] == x[i + 1]) {
      cnt++;
      if (x[i] == 'a')
        x[i] = 'b';
      else
        x[i] = 'a';
    }
  }
  cout << cnt << '\n';
  cout << x << '\n';
  return 0;
}
