#include <fstream>
using namespace std;
ifstream f("text.in");
ofstream c("text.out");
int nr1,s;
char ch,ch1;
int main()
{
    ch1=f.get();
    while(f.get(ch)!=0)
    {

        if((ch>='a' && ch<='z') || (ch>='A' && ch<='Z') )
             s++;
             else
             if((ch1>='a' && ch1<='z') || (ch1>='A' && ch1<='Z') )
             nr1++;
       ch1=ch;
        }

    c<<s/nr1;
    return 0;
}