#include<cstdio>
#include<cstring>
#include<iostream>
using namespace std;
int i,k,n,m,p,g,s;
char a[1000001],c[101],b[50000][100];
int main()
{
    freopen("text.in","r",stdin);
    freopen("text.out","w",stdout);
    cin.get(a,1000001);
    cin.get();
    n=strlen(a);
    for(i=0;i<=n-2;i++)
        while(strchr("',. ?!-0123456789",a[i])!=0&&strchr(",. ?!-0123456789",a[i+1])!=0&&i<n-1)
        {
            strcpy(a+i,a+i+1);
            n--;
        }
    for(i=0;i<=n-1;i++)
        if((a[i]>='a'&&a[i]<='z')||(a[i]>='A'&&a[i]<='Z'))
        {
            p=i;
            break;
        }
    m=-1;
    k=0;
    for(i=p;i<=n-1;i++)
        if((a[i]>='a'&&a[i]<='z')||(a[i]>='A'&&a[i]<='Z'))
        {
            m++;
            c[m]=a[i];
        }
        else
        {
            m++;
            c[m]='\0';
            k++;
            strcpy(b[k],c);
            m=-1;
        }
    s=0;
    for(i=1;i<=k;i++)
        s=s+strlen(b[i]);
    g=s/k;
    printf("%d\n",g);
    return 0;
}