#include <iostream>
#include <fstream>

using namespace std;

char x;

ifstream fin("text.in");
ofstream fout("text.out");

int main()
{
    int cuvinte = 0, litere = 0;
    while(!fin.eof()){
        fin.get(x);
        if((int)x >= 65 && (int)x <= 90 || (int)x >= 97 && (int)x <= 122) litere++;
        else if((int)x == 32 || (int)x == 63 || (int)x == 33 || (int)x == 46)
            cuvinte++;
    }
    //cout << litere <<" "<< cuvinte << " ";
    fout << litere / cuvinte;
    return 0;
}