import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {


	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String s = sc.next();
		List<Character> sList = new ArrayList<>();
		List<Character> yukiList = new ArrayList<>();

		yukiList.add('y');
		yukiList.add('u');
		yukiList.add('k');
		yukiList.add('i');

		int yCountup = 0;
		int yCount = 0;
		int uCountup = 0;
		int uCount = 0;
		int kCountup = 0;
		int kCount = 0;
		int iCount = 0;

		for (int i = 0; i < n; i++) {
			sList.add(s.charAt(i));
			if (sList.get(i) > 'y') {
				yCountup++;
			} else if(sList.get(i) == 'y') {
				yCount++;
			} else if (sList.get(i) > 'u') {
				uCountup++;
			} else if(sList.get(i) == 'u') {
				uCount++;
			} else if (sList.get(i) > 'k') {
				kCountup++;
			} else if(sList.get(i) == 'k') {
				kCount++;
			} else if (sList.get(i) > 'i') {
				iCount++;
			}
		}

		int luck = 0;

		luck += yCountup;

		for (int i = 1; i <= yCount; i++) {
			if (yCount-- > 0) {
				luck++;
				continue;
			}

			if (uCountup-- > 0 ) {
				luck++;
				continue;
			}

			if (uCount-- > 0) {
				if (kCountup > 0) {
					kCountup--;
					luck++;
					continue;
				}

				if (kCount > 0) {
					kCount--;
					if (iCount > 0) {
						iCount--;
						luck++;
						continue;
					}
					if (kCount > 0) {
						kCount--;
						luck++;
						continue;
					}
				}
				if (uCount-- > 0) {
					luck++;
				}
			}

		}

		System.out.println(luck);

	}
}