#include <fstream>
using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");

char caracter[1000001];
int litere,cuvinte,i;


int main()
{
    while(fin>>caracter)
    {
        for(i=0;i<=caracter[i];i++)
        {
            if((caracter[i]>='a' && caracter[i]<='z') || (caracter[i]>='A' && caracter[i]<='Z'))
            {
                while ((caracter[i]>='a' && caracter[i]<='z') || (caracter[i]>='A' && caracter[i]<='Z'))
                {
                    i++;
                    litere++;
                }
                cuvinte++;
            }
            else i++;
        }
    }
    fout<<litere/cuvinte;
    return 0;
}