#include <fstream>
#include <cstring>
#include <ctype.h>
using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");
int i,nrlitere,nrcuv;
char sir[500000],*p,sir2[500000];
int main()
{
    fin.getline(sir,500000);
    p=strtok(sir," ,!-;.?'");
    while(p)
    {

        if(isdigit(p[0])==0)
        {nrcuv++;
            for(i=0;i<strlen(p);i++)
            nrlitere++;}
            p=strtok(NULL," ,!-;.?'");
    }
    fout<<nrlitere/nrcuv;
}