#include <bits/stdc++.h>
using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");
long long cnt,length;
char s[100000010], delim[]=" -,.!?`=[]'/\{}:<>_+",*p;
int main() {
    fin.getline(s,100000000);
    for (int i=0;s[i]!=0;i++) {
        if ((s[i]>='0'&&s[i]<='9')||(s[i]>='a'&&s[i]<='z')||(s[i]>='A'&&s[i]<='Z'))
            length++;
    }
    p=strtok(s,delim);
    while (p!=nullptr) {
        p=strtok(nullptr,delim);
        cnt++;
    }
    fout<<1LL*length/cnt;
    return 0;
}