// #includes {{{
#include <bits/stdc++.h>
using namespace std;

#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define RREP(i,a,b) for(int i=(int)(a);i<(int)(b);++i)
#define FOR(i,c) for(__typeof((c).begin()) i=(c).begin();i!=(c).end();++i)
#define LET(x,a) __typeof(a) x(a)
//#define IFOR(i,it,c) for(__typeof((c).begin())it=(c).begin();it!=(c).end();++it,++i)
#define ALL(c) (c).begin(), (c).end()
#define MP make_pair

#define EXIST(e,s) ((s).find(e)!=(s).end())

#define RESET(a) memset((a),0,sizeof(a))
#define SET(a) memset((a),-1,sizeof(a))
#define PB push_back
#define DEC(it,command) __typeof(command) it=command

//debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#define debug_v(x) cerr << #x << " = [";REP(__ind,(x).size()){cerr << (x)[__ind] << ", ";}cerr << "] (L" << __LINE__ << ")" << endl;

#define whole(f,x,...) ([&](decltype((x)) whole) { return (f)(begin(whole), end(whole), ## __VA_ARGS__); })(x)

typedef long long Int;
typedef unsigned long long uInt;
typedef long double rn;

template<class T>
T inf(){
	return numeric_limits<T>::has_infinity?numeric_limits<T>::infinity():(numeric_limits<T>::max()/2);
}

typedef pair<int,int> pii;

/*
#ifdef MYDEBUG
#include"debug.h"
#include"print.h"
#endif
*/
// }}}

//{{{ io
FILE *file_in=stdin,*file_out=stdout;
#define fin normal_in
#define fout normal_out
//const char fname[]="";
//FILE *fin=fopen(fname,"r"),*fout=fopen(fname,"w");
#ifdef __MINGW32__
#define LLD "%I64d"
#define LLU "%I64u"
#else
#define LLD "%lld"
#define LLU "%llu"
#endif
struct NORMAL_IN{
	bool cnt;
	NORMAL_IN():cnt(true){}
	operator int() const {return cnt;}
#define endl "\n"
	NORMAL_IN& operator>>(int &n){cnt=fscanf(file_in,"%d",&n)!=EOF;return *this;}
	NORMAL_IN& operator>>(unsigned int &n){cnt=fscanf(file_in,"%u",&n)!=EOF;return *this;}
	NORMAL_IN& operator>>(long long &n){cnt=fscanf(file_in,LLD,&n)!=EOF;return *this;}
	NORMAL_IN& operator>>(unsigned long long &n){cnt=fscanf(file_in,LLU,&n)!=EOF;return *this;}
	NORMAL_IN& operator>>(double &n){cnt=fscanf(file_in,"%lf",&n)!=EOF;return *this;}
	NORMAL_IN& operator>>(long double &n){cnt=fscanf(file_in,"%Lf",&n)!=EOF;return *this;}
	NORMAL_IN& operator>>(char *c){cnt=fscanf(file_in,"%s",c)!=EOF;return *this;}
	NORMAL_IN& operator>>(string &s){
		s.clear();
		for(bool r=false;;){
			const char c=getchar();
			if(c==EOF){ cnt=false; break;}
			const int t=isspace(c);
			if(!r and !t)r=true;
			if(r){
				if(!t)s.push_back(c);
				else break;
			}
		}
		return *this;
	}
	template<class T>
		NORMAL_IN& operator>>(vector<T> &v){
			int v_size = v.size();
			REP(i,v_size){
				*this>>v[i];
			}
			return *this;
		}
} normal_in;

struct NORMAL_OUT{
	NORMAL_OUT& operator<<(const int &n){fprintf(file_out,"%d",n);return *this;}
	NORMAL_OUT& operator<<(const unsigned int &n){fprintf(file_out,"%u",n);return *this;}
	NORMAL_OUT& operator<<(const long long &n){fprintf(file_out,LLD,n);return *this;}
	NORMAL_OUT& operator<<(const unsigned long long &n){fprintf(file_out,LLU,n);return *this;}
	NORMAL_OUT& operator<<(const double &n){fprintf(file_out,"%lf",n);return *this;}
	NORMAL_OUT& operator<<(const long double &n){fprintf(file_out,"%Lf",n);return *this;}
	NORMAL_OUT& operator<<(const char c[]){fprintf(file_out,"%s",c);return *this;}
	NORMAL_OUT& operator<<(const string &s){fprintf(file_out,"%s",s.c_str());return *this;}
} normal_out;
struct ERR_OUT{
	template<class T>
		ERR_OUT& operator<<(const T &a){
			cerr<<"\x1b[7m"<<a<<"\x1b[m";
			return *this;
		}
} ferr;
//}}}


const int MOD = 1000000007;

//{{{ modular algebra
template<int mod=MOD>
struct Num{
	int v;
	Num(int n):v(n){}
	Num():v(0){}
	operator int() const {return v;}
	operator long long() const {return v;}
	template<class T>
	Num operator =(int n){v=n;return *this;}

	template<class T>
	inline void operator *=(const T &a) {
		v = (v*(long long)a)%mod;
	}
	template<class T>
	inline Num operator *(const T &a) {
		Num n(*this);n*=a;
		return n;
	}
	template<class T>
	inline void operator+=(const T &a){
		v+=(int)a;
		if(v>=mod)v-=mod;
		//	assert(0<=v and v<mod);
	}
	template<class T>
	inline Num operator+(const T &a){
		Num n(*this);n+=a;
		return n;
	}
	inline Num operator -(){
		if(v==0)return 0;
		else return Num(mod-v);
	}
	template<class T>
	inline void operator -=(const T &a){
		v-=(int)a;
		if(v<0)v+=mod;
	}
	template<class T>
	inline Num operator -(const T &a){
		Num n(*this);n-=a;
		return n;
	}
#ifdef __GCD_H
	inline Num inv(){
		return Num(invMod(this->v,mod));
	}
	template<class T>
	inline void operator /=(const T &a){
		(*this)*=invMod((int)a,mod);
	}
	template<class T>
	inline Num operator /(const T &a){
		Num n(*this);n/=a;
		return n;
	}
#endif
};

template<class T, int mod>
T& operator <<(T &os, const Num<mod> &n){
	os<<(int)n.v;
	return os;
}

template<class T, int mod>
T& operator >>(T &is, Num<mod> &n){
	is>>n.v;
	return is;
}
//}}}
typedef Num<MOD> mod_int;

Int N;
string S;

void solve(){
	vector<int> ct(26,0);
	REP(i,N)ct[S[i]-'a']++;
	mod_int ans = 1;
	REP(i,26)ans *= ct[i]+1;
	fout<<(ans-1)<<endl;
}


//{{{ main function
int main(){
    fin >> N;
    fin >> S;
    solve();
    return 0;
}

//}}}



Measured memory_bytes: 512