#include <fstream>
#include <cstring>
#define DIM 1100000

using namespace std;

char s[DIM];//1 MB = 1024 * 1024 B

inline bool CheckLetter(char x)
{
	return ('a' <= x && x <= 'z') || ('A' <= x && x <= 'Z');
}

int main()
{
	ifstream fin("text.in");
	fin.close();
	int sum = 0, cnt = 0;
	while (fin.getline(s, 1100000))
	{
		int n = strlen(s);
		for (int i = 0;i < n;++i)
		{
			if (CheckLetter(s[i]))
			{
				++cnt;
				while (CheckLetter(s[i]))
				{
					sum++;
					i++;
				}
			}
		}
	}
	ofstream fout("text.out");
	fout << sum / cnt << "\n";
	fout.close();
	return 0;
}