#include<cmath>

#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

const int N=(<<)+;

const double pi=acos(-);

const int mod=1e9+;

char s[N];

int n;

struct Complex

{

    double x,y;

    Complex(double x_=,double y_=):x(x_),y(y_){}

    Complex operator + (Complex P)

    {

        return Complex(x+P.x,y+P.y);

    }

    Complex operator - (Complex P)

    {

        return Complex(x-P.x,y-P.y);

    }

    Complex operator * (Complex P)

    {

        return Complex(x*P.x-y*P.y,x*P.y+y*P.x);

    }

};

typedef Complex E;

E a[N],b[N];

int rev[N];

int f[N];

char t[N];

int p[N];

int Pow(int a,int b)

{

    int res=;

    for(;b;b>>=,a=1LL*a*a%mod)

        if(b&) res=1LL*res*a%mod;

    return res;

}

void fft(E *a,int len,int tag)

{

    for(int i=;i<len;++i)

        if(i<rev[i]) swap(a[i],a[rev[i]]);

    for(int i=;i<len;i<<=)

    {

        E wn(cos(pi/i),tag*sin(pi/i));

        for(int p=i<<,j=;j<len;j+=p)

        {

            E w(,);

            for(int k=;k<i;++k,w=w*wn)

            {

                E x=a[j+k],y=a[j+k+i]*w;

                a[j+k]=x+y; a[j+k+i]=x-y;

            }

        }

    }

    if(tag==-)

    {

        for(int i=;i<len;++i) a[i].x=(a[i].x+0.5)/len;

    }

}

int solve_all()

{

    for(int i=;i<n;++i)

        if(s[i]=='a') a[i].x+=; else b[i].x=;

    int num=n*-,len=,bit=;

    while(len<num) len<<=,bit++;

    for(int i=;i<len;++i) rev[i]=(rev[i>>]>>)|((i&)<<bit-);

    fft(a,len,);

    for(int i=;i<len;++i) a[i]=a[i]*a[i];

    fft(a,len,-);

    fft(b,len,);

    for(int i=;i<len;++i) b[i]=b[i]*b[i];

    fft(b,len,-);

    for(int i=;i<len;++i) f[i]=a[i].x+b[i].x;

    int sum=;

    for(int i=;i<len;++i)

    {

        sum+=Pow(,f[i]+>>)-;

        sum-=sum>=mod ? mod : ;

    }

    return sum;

}

void manacher(int m)

{

    int id=,pos=,x=;

    for(int i=;i<=m;++i)

    {

        if(pos>i) x=min(p[id*-i],pos-i);

        else x=;

        while(t[i-x]==t[i+x]) x++;

        if(i+x>pos) pos=i+x,id=i;

        p[i]=x;

    }

}

int solve_continuous()

{

    int m=;

    t[m]='!';

    for(int i=;i<n;++i)

    {

        t[++m]='#';

        t[++m]=s[i];

    }

    t[++m]='#';

    t[m+]='@';

    manacher(m);

    int sum=;

    for(int i=;i<=m;++i)

    {

        sum+=p[i]>>;

        sum-=sum>=mod ? mod : ;

    }

    return sum;

}

int main()

{

    scanf("%s",s);

    n=strlen(s);

    int t1=solve_all();

    int t2=solve_continuous();

    printf("%d",(t1-t2+mod)%mod);

}