#include <fstream>
using namespace std;
ifstream is ("text.in");
ofstream os ("text.out");
int Lit (char x);
int main()
{
    int l = 0, cuv = 0;
    string s;
    while( is >> s)
    {
        cuv++;
        for (int i = 0; i < s.length(); ++i)
        {
            if ( !Lit(s[i]))
                l++;
            else
            {

                if (!Lit(s[i-1]) && !Lit(s[i+1]))
                    cuv++;

            }

        }
    }
    os << l / cuv;

    return 0;
}
int Lit (char x)
{
    if (x > 96 && x < 123)
        return false;
    if ( x > 64 && x < 91)
        return false;
    return true;
}