CntSubsirMax

#include<bits/stdc++.h>
using namespace std;
ifstream fin("window.in");
ofstream fout("window.out");
char s[1000005];
long long n;
long long f[30],r;
const long long mod=1e9+7;
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cin>>(s+1);
    n=strlen(s+1);
    for(long long i=1;i<=n;i++){
        r+=(i*(n-i+1))%mod;
        if(r>=mod)r-=mod;
    }
    for(long long i=n;i>=1;i--){
        long long mn(1e9+7);
        for(long long j=(long long)s[i]-95;j<=26;j++){
            mn=min(mn,((f[j])?f[j]:mod));
        }
        if(mn<1e9+7){
            r-=(i*(n-mn+1))%mod;
            r+=mod;
            r%=mod;
        }
        f[(long long)s[i]-96]=i;
    }
    cout<<r;
    return 0;
}