#include <bits/stdc++.h>
using namespace std;
ifstream in("text.in");
ofstream out("text.out");
int main()
{
    char s1[1024];
    in.getline(s1,1024);
    int l=0,n=0,s=0;
    for(int i=0;i<strlen(s1);i++)
    {
        if(isalpha(s1[i])) l++;
        if(strchr(" -,!?;.",s1[i]))
        { s+=l; n++; l=0;}
    }
    out<<s/n;
    return 0;
}