#include <fstream>
#include <iostream>
#include <string.h>
using namespace std;

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

int main()
{
	char buffer[255];
	bool gotWord = false;
	int i,alen,wlen,tlen=0,wcount=0;
	while(fin.get(buffer,255))
	{
		alen = strlen(buffer);
		for(i=0;i<alen;i++)
		{
			if((buffer[i] >= 'a' && buffer[i] <= 'z') || (buffer[i] >= 'A' && buffer[i] <= 'Z'))
			{
				wlen++;
				gotWord = true;
			}
			else
			{
				if(gotWord)
				{
					tlen += wlen;
					wcount++;
				}
				gotWord = false;
				wlen = 0;
			}
		}
	}
	fout<<tlen/wcount;
}