#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
char s[1000001];
char* point;
char* v[10001];
int i, med;
int main()
{
  f.getline(s,1000001);
  point = strtok(s," ,.123456789:;'-");
  while(point)
  {
    v[++i]=point;
    med+=strlen(v[i]);
    point=strtok(NULL," ,.123456789:;'");
  }
  g << med/i << endl;
  return 0;
}