#include <iostream>
#include <fstream>
#include <cstring>
#define nmax 2000000

using namespace std;

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

char v[nmax];
char tok[]=".!- ?,:;";
long long S,nr;
bool lit(char c)
{
    if((c>='a' && c<='z') || (c>='A' && c<='Z'))return 1;
    return 0;
}
int main()
{
    f.getline(v,nmax);
    long long n=strlen(v);
    long long l=0;
    for(long long i=0;i<n;i++)
    {
    if(lit(v[i]))
        {
            l++;
        }
        else
            {
                if(l)
                    {
                    nr++;
                    S+=l;
                    l=0;
                    }
            }
    }
    cout<<S/nr;
    return 0;
}