#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");

int main()
{
    char s[5000],*p;
    int i,nrl=0,nrc=0;
    f.getline(s,5000);
    for (i=0;s[i];i++)
        if (isalpha(s[i]))
        nrl++;
    p=strtok(s," -,!?.;:");
    while (p)
    {
        nrc++;
        p=strtok(NULL," -,!?.;:");
    }
    g<<nrl/nrc;
    return 0;
}