#include <iostream>
#include <fstream>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
string v;
int p,k,i,lit;
int main()
{
    f.get();
    getline(f,v); v[-1]='2';
    for (i=0;i<=v.size()-1;i++){
        if ((v[i]>='a' && v[i]<='z') || (v[i]>='A' && v[i]<='Z')){
            lit++;
            if ((v[i-1]<'A' || v[i-1]>'z') || (v[i-1]>'Z' &&v[i-1] <'a')) p++;
        }
    }
    g<<lit/p;
    return 0;
}