#include <cstdio>
#include <cstring>
#include <cctype>
#define MAX 1500000
using namespace std;
int nr,tot,ok;
char sir[MAX],*p,sep[]=",. !?'-;";
int verific(char s[MAX]);
int main()
{
    freopen("text.in","r",stdin);
    freopen("text.out","w",stdout);
    gets(sir);
    p=strtok(sir,sep);
    while(p!=NULL)
    {
        ok=verific(p);
        if(ok){
        nr++;
        tot+=strlen(p);}
        p=strtok(NULL,sep);
    }
    if(nr and tot)
    printf("%d",tot/nr);
    else
    printf("0");
    return 0;
}
int verific(char s[MAX])
{
    int i,l;
    l=strlen(s);
    for(i=0;i<l;++i)
        if(isdigit(s[i]))
            return 0;
    return 1;
}