#include<fstream>
#include<cstring>
using namespace std;
ifstream in("text.in");
ofstream out("text.out");
char s[1084000];

int main ()
{
    int suma=0,nr=0,i;
    while(in.getline(s,1000))
    {
        for(i=0;i<strlen(s);i++)
        {
            if(s[i]>='a' && s[i]<='z')
            {
                nr++;
                while(s[i]>='a' && s[i]<='z')
                {
                    suma++;
                    i++;
                }
            }
        }
    }
    out<<suma/nr<<'\n';
    return 0;
}