#include #define rep(i,n) for(int i=0;i<(n);i++) using namespace std; class rolling_hash{ static const long long base=10007,mod1=1e9+7,mod2=1e9+9; int len; vector pow1,pow2,h1,h2; public: using hash_type=pair; rolling_hash(const string& s):len(s.length()),pow1(len+1),pow2(len+1),h1(len+1),h2(len+1){ pow1[0]=pow2[0]=1; rep(i,len){ pow1[i+1]=pow1[i]*base%mod1; pow2[i+1]=pow2[i]*base%mod2; h1[i+1]=(h1[i]*base+s[i])%mod1; h2[i+1]=(h2[i]*base+s[i])%mod2; } } hash_type get_hash(int l,int r)const{ assert(0<=l && l<=r && r<=len); auto res1=(h1[r]-h1[l]*pow1[r-l])%mod1; if(res1<0) res1+=mod1; auto res2=(h2[r]-h2[l]*pow2[r-l])%mod2; if(res2<0) res2+=mod2; return {res1,res2}; } static hash_type get_hash(const string& s){ long long res1=0,res2=0; rep(i,s.length()){ res1=(res1*base+s[i])%mod1; res2=(res2*base+s[i])%mod2; } return {res1,res2}; } }; class mint{ static const int MOD=1e9+7; int x; public: mint():x(0){} mint(long long y){ x=y%MOD; if(x<0) x+=MOD; } mint& operator+=(const mint& m){ x+=m.x; if(x>=MOD) x-=MOD; return *this; } mint& operator-=(const mint& m){ x-=m.x; if(x< 0) x+=MOD; return *this; } mint& operator*=(const mint& m){ x=1LL*x*m.x%MOD; return *this; } mint& operator/=(const mint& m){ return *this*=inverse(m); } mint operator+(const mint& m)const{ return mint(*this)+=m; } mint operator-(const mint& m)const{ return mint(*this)-=m; } mint operator*(const mint& m)const{ return mint(*this)*=m; } mint operator/(const mint& m)const{ return mint(*this)/=m; } mint operator-()const{ return mint(-x); } friend mint inverse(const mint& m){ int a=m.x,b=MOD,u=1,v=0; while(b>0){ int t=a/b; a-=t*b; swap(a,b); u-=t*v; swap(u,v); } return u; } friend istream& operator>>(istream& is,mint& m){ long long t; is>>t; m=mint(t); return is; } friend ostream& operator<<(ostream& os,const mint& m){ return os<>s; int n=s.length(); rolling_hash H(s); vector dp(n/2+1); dp[0]=1; for(int i=1;i