#include <bits/stdc++.h>
using namespace std;
bool contain_only_two_same_repeating_chars(string s) {
int len = s.length();
if (len % 2 != 0) return false;
for (int i = 0; i < len - 2; i++) {
if (s[i] != s[i + 2]) {
return false;
}
}
return true;
}
int main()
{
string s = "abababab";
if (contain_only_two_same_repeating_chars(s))
cout << "Yes";
else
cout << "No";
return 0;
}
/*
run:
Yes
*/