#include <bits/stdc++.h>
using namespace std;
double EPS = 1e-9;
int INF = 1 << 30;
long long INFL = 1LL << 60;
int main() {
  int n;
  cin >> n;
  string w;
  cin >> w;
  int ile = 0;
  for (int i = 1; i < n; i += 2) {
    if (w[i] == 'a' && w[i - 1] == 'a') {
      w[i] = 'b';
      ile++;
    }
    if (w[i] == 'b' && w[i - 1] == 'b') {
      w[i] = 'a';
      ile++;
    }
  }
  cout << ile << "\n" << w;
}
