#include <bits/stdc++.h>
#define NMAX 10000005
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
char s[NMAX],*p;
int main()
{
    f.getline(s,NMAX);
    unsigned long long cuv,lit;
    cuv=lit=0;
    p=strtok(s," ,.-?!;':`");
    while (p != NULL)
    {
        cuv++;
        lit+=strlen(p);
        p=strtok(NULL, " ,.-?!;':`");
    }
    if (cuv!=0)
    g<<lit/cuv;
    else g<<0;
    return 0;
}