#include <functional> #include <iostream> #include <numeric> #include <vector> using namespace std; void bucket_sort(int M, vector<int>& arr, function<int(int)> cmp){ vector<vector<int>> buckets(M); for (int x : arr){ buckets[cmp(x)].push_back(x); } int idx = 0; for (int i = 0; i < M; i++){ for (int x : buckets[i]){ arr[idx++] = x; } } } int main(){ ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); string S; cin >> S; int N = S.size(); int G = 10; vector<int> masks(1 << G); iota(masks.begin(), masks.end(), 0); bucket_sort(G+1, masks, [](int mask){ return __builtin_popcount(mask); }); vector<long long> cost(1 << G, 1e18); cost[0] = 0; for (int mask : masks){ for (int i = 0; i < G; i++){ if (mask & (1 << i)) continue; int cnt_i = 0, cnt_s = 0; for (int j = 0; j < N; j++){ int g = S[j] - 'A'; if (g == i) cnt_i++; if (mask & (1 << g)) cnt_s++; } long long c = 0; int cnt_i_pre = 0, cnt_s_pre = 0; for (int j = 0; j < N; j++){ int g = S[j] - 'A'; if (g == i){ cnt_i--; c += min(cnt_i_pre + 2*cnt_s_pre, cnt_i + 2*cnt_s); cnt_i_pre++; } else if (mask & (1 << g)){ cnt_s_pre++; cnt_s--; } } cost[mask | (1 << i)] = min(cost[mask | (1 << i)], cost[mask] + c); } } long long ans = cost[(1 << G) - 1]; cout << ans / 2 << ((ans & 1) ? ".5" : "") << "\n"; return 0; }