#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    string s;
    cin >> s;
    int ans = 0;
    auto f = [&](string t) {
        return (t[0] == t[1] || t[1] == t[2]) && (t[0] != t[2]);
    };
    int n = s.size();
    rep(i, n - 2) {
        ans += f(s.substr(i, 3));
    }
    cout << ans << endl;
    return 0;
}