#include <bits/stdc++.h>
using namespace std;
long long pwr(long long base, long long p, long long mod) {
  long long ans = 1;
  while (p) {
    if (p & 1) ans = (ans * base) % mod;
    base = (base * base) % mod;
    p /= 2;
  }
  return ans;
}
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
long long lcm(long long a, long long b) { return a * (b / gcd(a, b)); }
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  int n;
  cin >> n;
  string str;
  cin >> str;
  int count = 0;
  for (int i = 0; i < n && i + 1 < n;) {
    if (str[i] == str[i + 1]) {
      count++;
      if (str[i] == 'a')
        str[i + 1] = 'b';
      else
        str[i + 1] = 'a';
    }
    i += 2;
  }
  cout << count << endl << str;
  return 0;
}
