// #pragma GCC optimize("Ofast,unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include <bits/stdc++.h>
#define ll long long int
#define vi vector<int>
#define vvi vector<vector<int>>
#define vll vector<long long>
#define vs vector<string>
#define vc vector<char>
#define vb vector<bool>
#define forn(i, s, n)  for(ll i=(ll)s; i<(ll)(n); i++)
#define all(c) c.begin(),c.end()
#define pb push_back
#define pll pair<long long int, long long int>
#define pii pair<int, int>
#define pss pair<string, string>
#define ull unsigned long long int
#define lld long double
#define F first
#define S second
#define PI 3.141592653589793238
#define prec(n) fixed<<setprecision(n)
#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>
#define debug(...) fprintf(stderr, __VA_ARGS__), fflush(stderr)
#define itsval(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); itval(_it, args); }
using namespace std;
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;

void itval(istream_iterator<string> it) {}
template<typename T, typename... Args>
void itval(istream_iterator<string> it, T a, Args... args) {
    cerr << *it << " = " << a << endl;
    itval(++it, args...);
}
const ll MOD = 1e9 + 7;
template <typename T>
inline void print(T x) {cout << x << "\n";}
template <typename T>
inline void printvec(T x) {for (auto a : x) cout << a << ' '; cout << '\n';}
// -----------------------------------------------------------------------

struct custom {
    bool operator()(const pair<int, pii> &p1, const pair<int, pii> &p2)const {

        return p1.F < p2.F;
    }
};

// Calculate a^b % MOD -------------------------------------------------
ll get_pow(ll a, ll b, ll M = MOD) {
    ll res = 1;
    while (b) {
        if (b & 1) res = (res * a) % M;
        a = (a * a) % M;
        b >>= 1;
    }
    return res;
}
// ---------------------------------------------------------------------
const ll N = 1e5 + 5, inf = 2e18;
lld dp[N];
void solve()
{
    ll n;
    cin >> n;
    lld ans = 0;
    forn(i, 1, n + 1)
    ans += ((lld)n) / (lld)i;
    cout << prec(10) << ans - 1;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output1.txt", "w", stdout);
#endif
    int test = 1;
    //cin >> test;
    clock_t z = clock();

    forn(tes, 0, test)
    {
        // cout << "Case #" << tes + 1 << ": ";
        solve();

    }
    debug("Total Time:%.4f\n", (double)(clock() - z) / CLOCKS_PER_SEC);
    return 0;
}
#include <stdio.h>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <cstdio>
#include <vector>
#include <string>
#include <bitset>
#include <cctype>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <numeric>
#include <complex>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <cassert>
#include <iostream>
#include <iterator>
#include <algorithm>
#include <functional>
//#include <atcoder/all>
//using namespace atcoder;
using namespace std;
typedef long long ll;
const double EPS = 1e-9;
typedef vector<int> vint;
typedef vector<vector<int>> v2int;
typedef vector<vector<vector<int>>> v3int;
typedef vector<ll> vll;
typedef vector<vector<ll>> v2ll;
typedef vector<vector<vector<ll>>> v3ll;
typedef list<int> liint;
typedef pair<int, int> pint;
typedef vector<pair<int, int>> vpint;
typedef vector<pair<ll, ll>> vpll;
typedef vector<pair<ll, int>> vpll_int;
typedef vector<pair<int, ll>> vpint_ll;
typedef set<pair<int, int>> spint;
typedef set<pair<ll, int>> spll;
typedef unordered_map<int, unordered_set<int>> Graph;
const int INF = int(2e9);
const ll LINF = ll(2e9) * ll(2e9);
#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for(int i = x; i < n; i++)
template<class T, class C> void chmax(T& a, C b) { a > b ? : a = b; }
template<class T, class C> void chmin(T& a, C b) { a < b ? : a = b; }



int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    string S;
    cin >> S;
    
    ll ans = 0;
    int N = S.size();
    unordered_map<char, int> num;
    for (int i = N - 1; i >= 1; i--) {
        if (S[i] == S[i - 1]) {
            ans += (N - 1 - i) - num[S[i]];
            REP(c, 'a', 'z' + 1) {
                num[c] = 0;
            }
            num[S[i]] = N - i;
        }
        else {
            num[S[i]]++;
        }
    }
    cout << max(0LL, ans) << endl;
    return 0;
}