#include <fstream>
#include <string.h>

using namespace std;

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

char S[10001];

int main()
{
    char * p;
    int K = 0 , nrC = 0;
    fin.getline(S , sizeof(S));
    for(int i = 0 ; i < strlen(S) ; i++)
    {
        if(S[i] >= 'a' && S[i] <= 'z' || S[i] >= 'A' && S[i] <= 'Z') nrC++;
    }
    p = strtok(S , ",.!- ");
    while(p)
    {
        K++;
        p = strtok(NULL , ",.!- ");
    }
    fout << nrC / K;

    return 0;
}