#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <list>
#include <queue>
#include <deque>
#include <string>
using namespace std;

vector <int> symbolsNum(1000, 0);
priority_queue <pair <int, int>, vector < pair <int, int> >, greater < pair <int, int> > > qSymbols;
vector <pair <int, int> > vertex;

int main()
{
    char inp = ' ';
    while(cin.get(inp))
    {
        if(int(inp) != 10)
        {
            symbolsNum[int(inp)]++;
        }
    }
    for(int i = 0; i < 1000; i++)
    {
        if(symbolsNum[i])
        {
            vertex.push_back(make_pair(symbolsNum[i], -1));
        }
    }
    if(vertex.size() == 1) // если один символ
    {
        cout << vertex[0].first;
        return 0;
    }
    sort(vertex.begin(), vertex.end());
    for(int i = 0; i < vertex.size(); i++)
    {
        qSymbols.push(make_pair(vertex[i].first, i));
    }
    while(qSymbols.size() != 1)
    {
        pair <int, int> v1, v2;
        v1 = qSymbols.top();
        qSymbols.pop();
        v2 = qSymbols.top();
        qSymbols.pop();
        int childNum = vertex.size();
        vertex[v1.second].second = childNum; // ставим индекс ребенка для обоих родителей
        vertex[v2.second].second = childNum;
        vertex.push_back(make_pair(v1.first + v2.first, -1));
        qSymbols.push(make_pair(v1.first + v2.first, childNum));
    }
    long long sum = 0;
    for(int i = 0; i < vertex.size() - 1; i++)
    {
        sum += vertex[i].first;
    }
    cout << sum;
    return 0;
}

/*

-------------
AAABCCD

13
---------------------
AaaaAaaaABbbCccCxD

50
------------------
AAaaBBbbCcccDdddEEEeeeFG
84
*/