#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
const long long M = 10000;
const int mod = 998244353;
const int inf = 100005;
void solve() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  int c = 0;
  for (int i = 1; i < n; i += 2) {
    if (s[i] == s[i - 1]) {
      c++;
      if (s[i - 1] == 'a')
        s[i] = 'b';
      else
        s[i] = 'a';
    }
  }
  cout << c << "\n";
  cout << s;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int T = 1;
  while (T--) {
    solve();
  }
  return 0;
}
