#include <iostream>
#include <fstream>
#include <string.h>

using namespace std;

ifstream f("text.in");
ofstream g("text.out");
int main()
{
    char t[10000000000000000],* p,sep[]=" ;:',.?";
    long nr=0,s=0;
    f.get(t,10000000000000000);
    p=strtok(t,sep);
    while(p!=NULL)
    {
        nr++;
        s+=strlen(p);
        p=strtok(NULL,sep);
    }
    g<<(long)s/nr<<'\n';
    return 0;
}