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

#define rep(i, a, b) for (ll i = a; i < b; i++)
using ll = long long;

int main(){
    string s;
    cin >> s;
    int n = s.size();
    int c = 0;
    rep(i, 0, n - 2) {
        set<char> st;
        rep(j, 0, 3) st.insert(s[j + i]);
        if((int)st.size() == 2 && (s[i] == s[i + 1] || s[i + 1] == s[i + 2]))
            c++;
    }
    cout << c << endl;
}