#include <bits/stdc++.h>
using namespace std;

int main() {
	string S;
	cin >> S;
	long long ans = 0;
	map<char, int> m;
	for (char c : S){
		for (auto [k, v] : m){
			if (k != c){
				ans += v * (v - 1) / 2;
			}
		}
		m[c]++;
	}
	cout << ans << '\n';
}