#include<fstream>
using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");
int lt,nrcuv;
char c,b='?';
bool litera (char x)
{
    int litera=0;

    if(((x>='A')&&(x<='Z'))||((x>='a')&&(x<='z')))
        litera=1;
    return litera;
}
int main()
{
    while(fin.get(c))
    {
       if(litera(c))
            lt++;

       if(litera(c)&&(!litera(b)))
       {nrcuv++;}

       b=c;
    }

    fout<<lt/nrcuv;
}