#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, c = 0, i;
  cin >> n;
  string s;
  cin >> s;
  for (i = 0; i < n; i = i + 2) {
    if (s[i] == 'a' && s[i + 1] == 'a') {
      c++;
      s[i] = 'b';
    }
    if (s[i] == 'b' && s[i + 1] == 'b') {
      c++;
      s[i] = 'a';
    }
  }
  cout << c << endl;
  cout << s;
  return 0;
}
