#include <iostream>
using namespace std;

struct digits
{
    unsigned freq;
    char letter;
};

int main()
{
    digits digit[26];
    for (short i = 0; i < 26; i++)
    {
        digit[i].letter = ('a' + i);
        digit[i].freq = 0;
    }
    char ch = 0;
    unsigned hivalue = 0;
    
    while (ch != '.')
    {
        cin.get(ch);
        for (short i = 0; i < 26; i++)
        {
            if (tolower(ch) == digit[i].letter)
                digit[i].freq++;
        }
    }
    
    for (short i = 0; i < 26; i++)
    {
        hivalue = 0;
        for (short i2 = 0; i < 26; i++)
        {
            if (digit[i].freq < hivalue)
                hivalue = 
}