#include <fstream>
#include<cstring>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
char m[101][101];
int main()
{
    unsigned int i=1,nr=0;;
    while(f>>m[i++]);
    for(unsigned int a=1;a<=i;a++)
            for(unsigned int j=0;j<strlen(m[a]);j++)
                if((m[a][j]>='a'&&m[a][j]<='z')||(m[a][j]>='A'&&m[a][j]<='Z'))
                            nr++;

            g<<nr/(i-2);
}