#include<fstream>
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<sstream>
using namespace std;
ifstream fi("text.in");
ofstream fo("text.out");stringstream f;
int main()
{char x[1254];char g;
char t[1254];int n=0,i,s=0,l=1,r=0;;char d[52]={'A', 'a','b','B','c','C','d','D','e','E','f','F','g','G','h','H','i','I','j','J','k','K','l','L','m','M','n','N','o','O','p','P','r','R','s','S','t','T','q','Q','u','U','v','V','w','W','X','x','y','Y','z','Z'};
while(fi.get(x,1254))
{
    f.clear();
    f.str(x);n=0;
    while(!f.eof()){
        f>>t;
        if(t[0]=='-'&&r==0)
            l--;
        r=1;
       l++;s+=strlen(t);int p=0;
        for(i=0;i<strlen(t);i++){p=0;
            for(int j=0;j<51;j++)
            if(t[i]==d[j])
            {
                p=1;j=52;
            }if(!p)
            s--;}
    }
        fo<<s/l;
        return 0;

}
}