#include <fstream>
#include <iostream>
#include <cstring>
using namespace std;
ifstream f ("text.in");
ofstream g ("text.out");
char x[10000001],dm[]="-_+*/,.!? 123456789";
int main()
{
    int lung_totala,nr;
    nr=lung_totala=0;
    f.get(x,100000001);
    char*p=strtok(x,dm);
    while(p!=NULL)
    {
        lung_totala+=strlen(p);
        nr++;
        p=strtok(NULL,dm);
    }
    if(nr!=0)
        g<<lung_totala/nr;
    else
        g<<0;
    return 0;
}