#include <fstream>
#include <iostream>
#include <string.h>
using namespace std;

ifstream fin("text.in");
ofstream fout("text.out");
 int main()
 {char a[1000];
  int nr=0,litere=0,k;
  while(!fin.eof())
    {fin>>a;
    nr++;
    k=strlen(a);
    for(int i=1;i<=strlen(a);i++)
        {if(a[i]=='!'||a[i]=='?'||a[i]=='.'||a[i]==','||a[i]=='-'||a[i]==':'||a[i]=='"'||a[i]=='/'||a[i]=='<'||a[i]=='>'||a[i]=='_') k--;


        }
    litere=litere+k;
    }
    fout<<litere/nr;


   return 0;
 }