#include <fstream>
#include <Cstring>
using namespace std;

ifstream is("text.in");
ofstream os("text.out");

int lun, cuv;
char c[1000000];
char delim[100] = " -,.:;'\"\|/+=_[]{}()~`!@#$%^&*<>?0123456789";
char *p;

int main()
{
    is.getline(c, 1000000, 'EOF');
    p = c;
    //strpbrk
    lun = strlen(c);
    do
    {
        p = strpbrk(p, delim);
        --lun;
        //os << p << "\n";
        p ? ++p : p;
        if ( p && isalpha(*p) )
            ++cuv;
    } while ( p );
    os << lun/cuv;
    is.close();
    os.close();
    return 0;
}