#include<fstream>
//#include<ctype.h>
#include<stdio.h>
//#include<conio.h>
//#include<iostream.h>

using namespace std;
ifstream f("text.in");
ofstream o("text.out");

char s[1024][1024];
int i=1,n,m=0,j,n1;

int main()
{
f>>s[i];
 while(!f.eof())
 {n=i; i++;  f>>s[i]; }

 for(i=1;i<=n;i++)
 {for(j=0;j<=' ' || j<=n;j++)
 if((int(s[i][j])>=65 && int(s[i][j])<=90) || (int(s[i][j])>=97 && int(s[i][j])<=122)  ) m++;
  }

o<<m/n<<"\n";

 return 0;
}