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

ifstream f("text.in");
ofstream g("text.out");

char c[1000001];
int main()
{
	int nr_cuv = 0, lungime_cuv = 0;
	f.get(c, 1000001);
	char* p = strtok(c, " ");
	while (p)
	{
		for (int i = 0; i < strlen(p); i++)
			if (isalpha(p[i]))
				lungime_cuv++;
		nr_cuv++;
		p = strtok(NULL, " ");
	}
	if (nr_cuv == 0)
		g << 0;
	else
	g << lungime_cuv / nr_cuv;
}