#include <fstream>
using namespace std;

ifstream f("text.in");
ofstream g("text.out");

int num,sum,ok,s;
char c;

int main()
{
    ok = false;
    while(f.good())
    {
        c = f.get();
        if((c>='a' && c<='z') || (c>='A' && c<='Z'))
        {
            if(ok)
                s++;
            else
            {
                ok = true;
                s = 1;
            }
        }
        else
        {
            if(s!=0)
            {
                num++;
                sum += s;
            }

            s = 0;
            ok = false;
        }
    }
    
    g<<sum/num;
    return 0;
}