#include <bits/stdc++.h>
using namespace std;
mt19937 rnd(chrono::high_resolution_clock::now().time_since_epoch().count());
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  string s;
  cin >> s;
  long long n = s.length(), ans = 0;
  long long a[n + 1];
  a[n - 1] = n;
  for (int i = n - 2; i >= 0; i--) {
    a[i] = a[i + 1];
    for (int k = 1; 2 * k + i < n; k++) {
      if (s[i] == s[i + k] && s[k + i] == s[2 * k + i]) {
        a[i] = i + 2 * k;
        break;
      }
    }
    a[i] = min(a[i], a[i + 1]);
    ans += n - a[i];
  }
  cout << ans << endl;
}
