#include <iostream>
#include <fstream>
using namespace std;


ifstream fin("text.in");
ofstream fout("text.out");


void solve()
{
    int l=0,s=0,nr=0;
    char c;
    while(fin.get(c))
    {
        if( ('a'<=c && c<='z') || ('A'<=c && c<='Z') )
        {
            l++;
        }
        else
        {
            if(l>0)
                nr++;
            s+=l;
            l=0;
        }
    }
    fout<<s/nr;
}



int main()
{
    solve();
    return 0;
}