#include <bits/stdc++.h>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");

int main()
{
string s;
int lung = 0 , litere = 0 ;
while(f>>s)
{
    lung++;
    int x=s.length();
    for(int i=0;i<=x;i++)
{
    if(s[i]>='a' && s[i]<='z')
        litere++;
    if(s[i]>='A' && s[i]<='Z')
        litere++;
        if((s[i]=='.' || s[i] == ',' || s[i] == '?' || s[i] == '!' || s[i] == '-')&&s[i+1]!='\0')
            lung++;
}
}
if(!lung)
    g<<0;
else
g<<litere/lung;
}