#include<cstdio>

using namespace std;

int m,n,u,f,d,sum,ans;
char str[2];

int main(){
	int i,j,k;
	scanf("%d %d %d %d %d",&m,&n,&u,&f,&d);
	u+=d;
	d+=u;
	f*=2;
	sum=0;
	ans=0;
	for(i=0;i<n;i++){
		scanf("%s",&str);
		if (str[0]=='u'){
			sum+=u;
		}else if (str[0]=='f'){
			sum+=f;
		}else{
			sum+=d;
		}
		if (sum<=m) ans=i+1;
	}
	printf("%d\n",ans);
	return 0;
}