#include<cstdio>
#include<cstring>
using namespace std;
int i, nr_cuv, sum, lg_cuv;
char c;
int main(){
    freopen("text.in","r",stdin);
    freopen("text.out","w",stdout);
    nr_cuv=0; sum=0; lg_cuv=0;
    while (scanf("%c", &c)!=EOF) {
        if (('a'<=c)&&(c<='z')) lg_cuv++; else {
            if (lg_cuv>0) {nr_cuv++; sum+=lg_cuv;}
            lg_cuv=0;
        }
    }
    printf("%d\n", sum/nr_cuv); return 0;
}