import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new FileReader("text.in"));
        PrintWriter out = new PrintWriter("text.out");

		int count = 0;
		int totalLength = 0;
		while(in.ready()) {
			String line = in.readLine();
			int lengthOfCurrentWord = 0;
			for(int i=0;i<line.length();i++) {
				if(Character.isAlphabetic(line.charAt(i))) {
					++lengthOfCurrentWord;
				} else {
				    if(lengthOfCurrentWord != 0) {
						++count;
						totalLength += lengthOfCurrentWord;
						lengthOfCurrentWord = 0;
				    }
				}
			}
		}
        out.printf("%d%n", totalLength/count);
		
        in.close();
        out.close();
	}
}