using System;
class Program
{
static bool contain_only_three_same_repeating_chars(string s) {
int len = s.Length;
if (len % 3 != 0) return false;
for (int i = 0; i < len - 3; i++) {
if (s[i] != s[i + 3]) {
return false;
}
}
return true;
}
static void Main() {
string s = "abcabcabcabc";
if (contain_only_three_same_repeating_chars(s))
Console.WriteLine("Yes");
else
Console.WriteLine("No");
}
}
/*
run:
Yes
*/