#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  string s;
  cin >> s;
  int op = 0;
  for (__typeof(n) i = (0) - ((0) > (n)); i != (n) - ((0) > (n));
       i += 1 - 2 * ((0) > (n))) {
    if (s[i] == s[i + 1]) {
      op++;
      if (s[i] == 'a')
        s[i + 1] = 'b';
      else
        s[i + 1] = 'a';
    }
    i++;
  }
  cout << op << "\n";
  cout << s;
  return 0;
}
