#include <iostream>
#include <algorithm>
using namespace std;
int n,d[9],z,x,o;
char y[4] = {'y','u','k','i'};
string s;
int main(){
	cin>>n>>s;
	for(int i=0; s.size()>i;i++){
		o=1;
		for(int j=0;8>j;j+=2){
			if(s[i]>=y[j/2]){
				o=0;
				d[j+(s[i]==y[j/2])]++;
				break;
			}
		}
		if(o)d[8]++;
	}reverse(d,d+9);
	z = (d[1]>d[0]?d[0]+(d[1]-d[0])/2:d[1]);
	for(int i = 2;7>i;i+=2){
		x = min(d[i],d[i+1]);
		if(d[i+1]>d[i]){
			d[i+1]-=d[i];
			x+=min(d[i+1],z);
			if(d[i+1]>z)x+=(d[i+1]-z)/2;
		}z=x;
	}
	cout <<z+d[8]<< endl;
}