#include<iostream>
#include<queue>
#include<string>
#include<stdio.h>
#include<cstring>

using namespace std;
int a[30];
int main()
{
    int len;
    int ans;
    int tmp;
    double cpsn;
    string s;

    while (cin >> s)
    {
        ans = 0;
		if (s == "END")  break;
        len = s.size();
        memset(a, 0, sizeof(a));

        for (int i = 0; i < len; i++)
        {

            if (s[i] == '_')
            {
                a[27]++;
            }else
            {
                a[s[i] - 'A']++;
            }
        }
        priority_queue<int, vector<int>, greater<int> > q;

        for (int i = 0; i <= 27; i++)
        {
            if (a[i] > 0)
                q.push(a[i]);
        }
		if (q.size() == 1) ans = q.top();  //考虑单一字符的字符串的特殊情况处理
        while (q.size() > 1)
        {
            tmp = q.top();
            q.pop();
            tmp += q.top()...