#include<iostream>

 #include<cstdio>

 #include<queue>

 #include<algorithm>

 #include<cmath>

 #include<ctime>

 #include<set>

 #include<map>

 #include<stack>

 #include<cstring>

 #define inf 2147483647

 #define ls rt<<1

 #define rs rt<<1|1

 #define lson ls,nl,mid,l,r

 #define rson rs,mid+1,nr,l,r

 #define N 100010

 #define For(i,a,b) for(int i=a;i<=b;i++)

 #define p(a) putchar(a)

 #define g() getchar()

 using namespace std;

 int n,ans;

 char c[];

 int a[],f1[],f2[],sum[];

 void in(int &x){

     int y=;

     char c=g();x=;

     while(c<''||c>''){

         if(c=='-')y=-;

         c=g();

     }

     while(c<=''&&c>=''){

         x=(x<<)+(x<<)+c-'';c=g();

     }

     x*=y;

 }

 void o(int x){

     if(x<){

         p('-');

         x=-x;

     }

     if(x>)o(x/);

     p(x%+'');

 }

 void clear(){

     memset(f1,,sizeof(f1));

     memset(f2,,sizeof(f2));

     memset(sum,,sizeof(sum));

     ans=;

 }

 int main(){

     while(cin>>n){

         clear();

         cin>>(c+);

         For(i,,n)

             a[i]=c[i]-'a'+;

         For(i,,n){

             For(j,,a[i]-)

                 f1[i]+=sum[j];

                 f1[i]++;

                 f1[i]%=;

                 sum[a[i]]+=f1[i];

             }

         memset(sum,,sizeof(sum));

         for(int i=n;i;i--){

             For(j,,a[i]-)

                 f2[i]+=sum[j];

                 f2[i]++;

                 f2[i]%=;

                 sum[a[i]]+=f2[i];

         }

         For(i,,n-){

             ans+=(f1[i]-)*(f2[i]-)%;

             ans%=;

         }

         o(ans);p('\n');

     }

     return ;

 }