import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class Main {
	static InputStream is;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve()
	{
		int n = ni();
		char[] s = ns(n);
		// ? i ? k ? u ? y ?
		int[] f = new int[9];
		String x = "yuki";
		outer:
		for(char c : s){
			for(int i = 0;i < 4;i++){
				if(c > x.charAt(i)){
					f[8-i*2]++;
					continue outer;
				}else if(c == x.charAt(i)){
					f[7-i*2]++;
					continue outer;
				}
			}
			f[0]++;
		}
		
		long ret = 0;
		ret += f[8]; f[8] = 0;
		long v = 0;
		v = Math.min(f[7], f[6]);
		ret += v; f[7] -= v; f[6] -= v;
		v = Math.min(Math.min(f[7], f[5]), f[4]);
		ret += v; f[7] -= v; f[5] -= v; f[4] -= v;
		v = Math.min(Math.min(Math.min(f[7], f[5]), f[3]), f[2]);
		ret += v; f[7] -= v; f[5] -= v; f[3] -= v; f[2] -= v;
		v = Math.min(Math.min(Math.min(Math.min(f[7], f[5]), f[3]), f[1]), f[0]);
		ret += v; f[7] -= v; f[5] -= v; f[3] -= v; f[1] -= v; f[0] -= v;
		
		int all = 100000;
		for(;all >= 0;all--){
			int lall = all;
			int[] g = Arrays.copyOf(f, 9);
			if(g[7]-lall < 0)continue;
			g[7] -= lall; lall -= g[7];
			if(lall < 0)break;
			if(g[5]-lall < 0)continue;
			g[5] -= lall; lall -= g[5];
			if(lall < 0)break;
			if(g[3]-lall < 0)continue;
			g[3] -= lall; lall -= g[3];
			if(lall < 0)break;
			if(lall*2 <= g[1])break;
		}
		out.println(ret+all);
		
		// 8
		// 77
		// 76
		// 755
		// 754
		// 7533
		// 7532
		// 75311
		// 75310
	}
	
	public static void main(String[] args) throws Exception
	{
		long S = System.currentTimeMillis();
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
	}
	
	private static boolean eof()
	{
		if(lenbuf == -1)return true;
		int lptr = ptrbuf;
		while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;
		
		try {
			is.mark(1000);
			while(true){
				int b = is.read();
				if(b == -1){
					is.reset();
					return true;
				}else if(!isSpaceChar(b)){
					is.reset();
					return false;
				}
			}
		} catch (IOException e) {
			return true;
		}
	}
	
	private static byte[] inbuf = new byte[1024];
	static int lenbuf = 0, ptrbuf = 0;
	
	private static int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private static double nd() { return Double.parseDouble(ns()); }
	private static char nc() { return (char)skip(); }
	
	private static String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private static char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private static char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private static int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private static int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}