#include <iostream>
#include <fstream>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
int i,j,l,lm;
char c,d;
int main()
{
    while(f>>noskipws>>c){if(c>='A'&&c<='z'||c>='0'&&c<='9')lm++;
                             else if(c>=' '&&c<'?'&&lm>0&&(d>='A'&&d<='z'||d>='0'&&d<='9'))l++;
                             d=c; }
    g<<lm/l;


    f.close();
    g.close();

    return 0;
}