#include<iostream>
#define MOD 1000000007
using namespace std;
int n,i,rez,F[100005];
char c;
int main()
{
    cin>>n;
	rez=1;
	for(i=1; i<=n; i++)
	{
        cin>>c;
        F[c-'a']++;
	}
    for(i=0; i<26; i++)
        rez=(1LL*rez*(F[i]+1))%MOD;
	cout<<(rez-1+MOD)%MOD<<"\n";
    return 0;
}
