#include <stdio.h>
#include <string.h>
FILE *in,*o;
char s[10000],sep[]="_ 1234567890,.?/!;\'-@#$%^&*(){}[]|:<>+~`",*a;
int n,nr,nrc,l,i,se,j;
float r;
main()
{
    in=fopen("clasic.in","r");
    o=fopen("clasic.out","w");
    while (!feof(in))
    {
        fgets(s,10000,in);
        n=strlen(s);
        for (i=0; i<n; i++)
        {
            if (s[i]<='z' && s[i]>='a' || s[i]<='Z' && s[i]>='A')
                nr++;
        }
        a=strtok(s,sep);
        if (a!=NULL)
            nrc++;
        while (a!=NULL)
        {
            nrc++;
            a=strtok(NULL,sep);
        }
        nrc--;
    }
    r=nr/nrc;
    fprintf(o,"%d",int(r));
    fclose(in);
    fclose(o);
    return 0;
}