#include <stdio.h>
#define MOD 1000000007

int x[200010];
char y[200010];
int start[200010],check[110];
long long int DP[200010][30];
int main()
{
	int a;
	scanf("%d",&a);
	for(int i=1;i<=a;i++) scanf("%d",&x[i]);
	scanf("%s",y+1);
	
	for(int i=1;i<=a;i++)
	{
		for(int j=0;j<26;j++) DP[i][j] = DP[i-1][j];
		long long int sum = 0;
		for(int j=0;j<26;j++) sum += DP[i-1][j], sum %= MOD;
		sum += (MOD-DP[i-1][y[i]-'a']+1), sum %= MOD;
		sum *= x[i], sum %= MOD;
		DP[i][y[i]-'a'] = DP[i-1][y[i]-'a'] + sum, DP[i][y[i]-'a'] %= MOD;
	}
	
	long long int ans = 0;
	for(int j=0;j<26;j++) ans += DP[a][j], ans %= MOD;
	printf("%lld",ans);
}