#include<fstream.h>
#include<ctype.h>
#include<string.h>
ifstream f("text.in");
ofstream g("text.out");
int i,l,n,k;
char s[1001],cuv[25];
int main (){
f.getline(s,1001);
i=0;
l=0;
n=0;
while(s[i]!=0){
while((isspace(s[i])||ispunct(s[i])||isdigit(s[i]))&&s[i]!=0)
i++;
k=0;
while((s[i]>='A'&&s[i]<='Z')||(s[i]>='a'&&s[i]<='z')&&s[i]!=0)
cuv[k++]=s[i++];
if(k!=0){
cuv[k]=0;
n++;
l=l+strlen(cuv);}}
g<<l/n;
f.close();
g.close();
return 0;}