{
	ll@a;
	string@b;
	ll n=b.size();
	Mint r1,r2,r3,r4;
	r1=b[0]-'1';
	rep(i,1,n){
		r1=r1*a+(b[i]-'0');
	}
	rep(i,2,n){
		r3=r3*a+1;
		r2=r2*a+r3;
	}
	wt((r1+1)*(n-1)+r2*(a-1)*a);
}