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