#include <fstream>
#include <cstring>
using namespace std;

ifstream fin("text.in");
ofstream fout("text.out");

char x[1024*1025];

int NrLitere,NrCuv;

int main()
{
    while(fin.getline(x,1024*1025))
    {
            for(int i = 0; x[i]; i++)
        {
            if ( (x[i]>=65 && x[i]<=90) || (x[i]>=97 && x[i] <= 122) )
                NrLitere++;
        }

    for(int i = 0; x[i];  )
        {
            if ( (x[i]>=65 && x[i]<=90) || (x[i]>=97 && x[i] <= 122) )
                {
                    while(( (x[i]>=65 && x[i]<=90) || (x[i]>=97 && x[i] <= 122) ) )
                        i++;
                    NrCuv++;
                }
            else
                i++;
        }

    }

    fout<<NrLitere/NrCuv<<"\n";

    return 0;
}