#include <bits/stdc++.h>
using namespace std;

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

char s[1000005];
int nrlitere, nrcuv;

int main()
{
    in.get(s, 1000005);
    int n = strlen(s);
    for (int i = 0;i < n;++i)
         if ((s[i] >= 'a' && s[i] <= 'z') || (s[i] >= 'A' && s[i] <= 'Z'))
             ++nrlitere;
    char *p = strtok(s, " ,.!-");
    while (p != NULL)
    {
        ++nrcuv;
        p = strtok(NULL, " ,.!-");
    }
    out<<nrlitere / nrcuv;
    return 0;
}