#include using namespace std; #define fast_io ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL) #define pb push_back #define int long long #define ll long long #define ld long double #define rep(i, n) for (ll i=0; i=0; i--) #define mem(v, ha) memset(v, ha, sizeof(v)) #define all(a) a.begin(), a.end() #define allr(a) a.rbegin(), a.rend() #define CLOCK cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n"; typedef vector vi; typedef vector> vvi; typedef vector> vpi; typedef vector vc; #define no cout << "NO\n" #define yes cout << "YES\n" #define mp make_pair #define ff first #define ss second const ll M = 1e9 + 7; const ll mod = 998244353 ; const long double PI = 3.141592653589793238460; const int inf = (int)(1e9); // auto sum=[&](int use, int y){return use+y;}; // function dfs=[&](int u) //void is the return type, int is the argument void solve() { string s; cin >> s; int n = s.size(); ll dp[n + 1] = {}; //iを右端にしたときの文字列の種類数の総和 vector pre(26, -1); double ans = 0; // cout << dp[0]; for (int i = 0; i < n; i++) { dp[i + 1] = dp[i] + i - pre[s[i] - 'a']; pre[s[i] - 'a'] = i; ans += dp[i + 1]; cout << dp[i + 1] << " " << ans << '\n'; //cout << ans << '\n'; } cout << setprecision(12) ; ans /= (double)n * (n + 1) / 2.0; cout << ans; } int32_t main() { fast_io; int T = 1; // cin >> T; while (T--) { solve(); } }