# include <fstream>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
int k,sum;
char c1,c2;
int main()
{
    c1=' ';sum=k=0;
    while( f.get(c2) )
    {
        if(((65<=c2)&&(c2<=90))||((97<=c2)&&(c2<=122)))sum++;
        else if(((65<=c1)&&(c1<=90))||((97<=c1)&&(c1<=122)))k++;
        c1=c2;
        if(c2=='\n')break;
    }
    g<<sum/k<<'\n';
}