#include <bits/stdc++.h>

using namespace std;
int input(){
    int res = 0; char c = ' ';
    while (c < '0') c = getchar();
    while (c >= '0') res = res * 10 + (c - '0'), c = getchar();
    return res;
}
const int N = 1e5 + 1, MOD = 1e9 + 7;

int sum(int f, int s){
    return (f + s < MOD ? f + s : f + s - MOD);
}
int dif(int f, int s){
    return (f - s < 0 ? f - s + MOD : f - s);
}
int f[N], cnt[10], a[N], cur;
int main(){
    int n = input();
    for (int i = 1; i <= n; ++ i){
        char c; cin >> c;
        a[i] = c - '0';
    }
    f[0] = 1;

    for (int i = 1, j = 1; i <= n; ++ cnt[a[i ++]]){
        while (cnt[a[i]]){
            cur = dif(cur, f[j]);
            -- cnt[a[j]], ++ j;
        }
        cur = sum(cur, f[i] = sum(cur, f[j - 1]));
    }
    cout << f[n];
}