#include <fstream>
#include <cstring>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
char s[1200000],*p;
int l=0,nr=0;
int main ()
{
    f>>s;
    p=strtok(s," -!?,.;:/'/"");
    while (p!=NULL)
    {
        nr++;
        l=l+strlen(p);
        p=strtok(NULL," -!?,.;:/'/"");
    }
    g<<l/nr;
    g.close();
    return 0;
}