#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 3;
char a[maxn];
int b[maxn];
int main() {
  int n, i, j;
  cin >> n >> a;
  int ans = 0;
  for (int i = 0; i < n; i++) b[i] = a[i] == 'a';
  for (int i = 0; i < n; i += 2) {
    if ((b[i] ^ b[i + 1]) == 0) b[i] ^= 1, ans++;
  }
  printf("%d\n", ans);
  for (int i = 0; i < n; i++) {
    if (b[i])
      printf("a");
    else
      printf("b");
  }
  return 0;
}
