#include <bits/stdc++.h>
using namespace std;
int dp[1010][1010];
int val[1010];
int main() {
  long long t;
  t = 1;
  while (t-- > 0) {
    long long n;
    string s;
    cin >> n >> s;
    long long ans = 0;
    for (int i = 0; i < n - 1; i += 2) {
      for (long long j = i; j <= i + 1; j++) {
        if (s[i] == s[i + 1]) {
          ans += 1;
          if (s[i] == 'a')
            s[i + 1] = 'b';
          else
            s[i + 1] = 'a';
        }
      }
    }
    cout << ans << endl;
    cout << s << endl;
  }
}
