#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1000000007;
long long int cnt[200005];
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL), cout.tie(NULL);
  long long int n, a = 0, b = 0, k1, k2, p, c, x, mx = 0, mn = 0, i, j,
                   flag = 0, cnt = 0;
  cin >> n;
  string s, s1, s2;
  cin >> s;
  for (i = 0; i < n - 1; i += 2) {
    if (s[i] == 'a' && s[i + 1] == 'a') {
      s[i + 1] = 'b';
      cnt++;
    } else if (s[i] == 'b' && s[i + 1] == 'b') {
      s[i + 1] = 'a';
      cnt++;
    }
  }
  cout << cnt << endl;
  cout << s << endl;
}
