#include <bits/stdc++.h>
using namespace std;
char s[200050];
int main() {
  int n;
  int ans;
  scanf("%d", &n);
  for (int i = 0; i <= n + 1; ++i) {
    scanf("%c", &s[i]);
  }
  ans = 0;
  for (int i = 2; i <= n; i += 2) {
    if (s[i] == s[i - 1]) {
      s[i] = s[i - 1] == 'a' ? 'b' : 'a';
      ans++;
    }
  }
  printf("%d\n", ans);
  for (int i = 1; i <= n; ++i) {
    printf("%c", s[i]);
  }
  printf("\n");
  return 0;
}
