#include <bits/stdc++.h>
using namespace std;
const long double PI = 2 * acos(0.0);
void yes() { cout << "YES\n"; }
void no() {
  cout << "NO\n";
  cout << -1 << "\n";
  exit(0);
}
long long m(long long a) { return (a + 1000000007) % 1000000007; }
long long cel(long long x1, long long y1) {
  ;
  if ((x1 % y1) == 0) return x1 / y1;
  return x1 / y1 + 1;
}
long long power(long long a, long long b) {
  if (b == 0) return 1;
  long long d = power(a, b / 2);
  d = m(d * d);
  if (b & 1) d = m(d * a);
  return d;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n;
  cin >> n;
  string str;
  cin >> str;
  long long k = 0;
  for (long long i = 0; i < n; i += 2) {
    if (str[i] != str[i + 1])
      continue;
    else {
      k++;
      if (str[i + 1] == 'a')
        str[i] = 'b';
      else
        str[i] = 'a';
    }
  }
  cout << k << "\n";
  cout << str;
}
