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

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

int main()
{
    char s[256],no_litere[]=" !%&()+,-./0123456789:;<=>?{|}~";
    int nrlitere=0,k=0,i;
    fin.get(s,256);
    for(int i=0;i<strlen(s)-1;i++)
    {
        if((s[i]>='a' && s[i]<='z') || (s[i]>='A' && s[i]<='Z'))
        {
            nrlitere++;
            if(strchr(no_litere,s[i+1]))
                k++;
        }
    }
    fout<<nrlitere/k;
}