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