# include <fstream>
# include <cstring>
# define DIM 1000010
using namespace std;
ifstream fin("text.in");
ofstream fout("text.out");
int nrc,nr,s,i;
char v[DIM];
int main () {
    fin.get(v,DIM-5);
    for(i=0;i<=strlen(v);i++){
        if((v[i]-'0'>=49&&v[i]-'0'<=74)||(v[i]-'0'>=17&&v[i]-'0'<=42))
            nr++;
        else{
            if((v[i-1]-'0'>=49&&v[i-1]-'0'<=74)||(v[i-1]-'0'>=17&&v[i-1]-'0'<=42)){
                s+=nr;
                nrc++;
                nr=0;
            }
        }
    }
    fout<<s/nrc<<"\n";
    return 0;
}