#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; namespace { using Integer = long long; //__int128; template istream& operator >> (istream& is, pair& p){return is >> p.first >> p.second;} template istream& operator >> (istream& is, vector& vec){for(T& val: vec) is >> val; return is;} template istream& operator , (istream& is, T& val){ return is >> val;} template ostream& operator << (ostream& os, const pair& p){return os << p.first << " " << p.second;} template ostream& operator << (ostream& os, const vector& vec){for(size_t i=0; i ostream& operator , (ostream& os, const T& val){ return os << " " << val;} template void print(const H& head){ cout << head; } template void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); } template void println(const T& ... values){ print(values...); cout << endl; } template void eprint(const H& head){ cerr << head; } template void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); } template void eprintln(const T& ... values){ eprint(values...); cerr << endl; } class range{ Integer start_, end_, step_; public: struct range_iterator{ Integer val, step_; range_iterator(Integer v, Integer step) : val(v), step_(step) {} Integer operator * (){return val;} void operator ++ (){val += step_;} bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;} }; range(Integer len) : start_(0), end_(len), step_(1) {} range(Integer start, Integer end) : start_(start), end_(end), step_(1) {} range(Integer start, Integer end, Integer step) : start_(start), end_(end), step_(step) {} range_iterator begin(){ return range_iterator(start_, step_); } range_iterator end(){ return range_iterator( end_, step_); } }; inline string operator "" _s (const char* str, size_t size){ return move(string(str)); } constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);} constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);} constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); } inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed mt19937 mt(chrono::duration_cast(chrono::steady_clock::now().time_since_epoch()).count()); template string join(const vector& v, const string& sep){ stringstream ss; for(size_t i=0; i0) ss << sep; ss << v[i]; } return ss.str(); } inline string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; } } constexpr long long mod = 9_ten + 7; #include class palindromic_tree{ public: struct node{ map e; int suf; int len; }; const string& s; vector t; vector s_pos; void constract(){ int pos = 1; for(int i=0; i= 0 && s[i-t[pos].len-1] == s[i]) break; pos = t[pos].suf; } if(t[pos].e.count(s[i])){ pos = t[pos].e[s[i]]; continue; } int nx = t.size(); t.push_back(node{{}, -1, t[pos].len+2}); t[pos].e[s[i]] = nx; if(t[nx].len == 1){ t[nx].suf = 1; pos = nx; continue; } while(1){ pos = t[pos].suf; if( i-t[pos].len-1 >= 0 && s[i-t[pos].len-1] == s[i]){ t[nx].suf = t[pos].e[s[i]]; break; } } pos = nx; } } void init(){ t[0].suf = 0; t[0].len = -1; t[1].suf = 0; t[1].len = 0; } palindromic_tree(const string& s_) : s(s_), t(2), s_pos(s_.size()){ init(); constract(); } }; int main(){ string s; cin >> s; palindromic_tree p(s); vector dp(s.size()+1, 0); vector dp_(s.size()+1, 0); using tt = tuple; deque g; for(int j=0; j g_; for(auto& t : g){ int i = get<0>(t), d = get<1>(t), k = get<2>(t); if(i && s[i-1] == s[j]){ g_.push_back( tt{i-1, d, k} ); } } deque g__; int r = -j-1; for(auto& t : g_){ int i = get<0>(t), d = get<1>(t), k = get<2>(t); if(i-r != d){ g__.push_back( tt{i,i-r,1} ); if( k>1 ){ g__.push_back( tt{i+d, d, k-1} ); } }else{ g__.push_back( tt{i,d,k} ); } r = i+(k-1)*d; } if( j && s[j-1] == s[j] ){ g__.push_back( tt{j-1, j-1-r, 1} ); r = j-1; } g__.push_back( tt{j,j-r,1} ); g.clear(); tt x = g__.front(); g__.pop_front(); while(g__.size()){ int& d_ = get<1>(x); int& k_ = get<2>(x); auto t = g__.front(); g__.pop_front(); int i = get<0>(t), d = get<1>(t), k = get<2>(t); if( d_ == d ) k_ += k; else{ g.push_back( x ); x = t; } } g.push_back( x ); for(auto& t : g){ int i = get<0>(t), d = get<1>(t), k = get<2>(t); r = i+(k-1)*d; long long unko = 0; if(r-1>=0){ unko += p.t[p.s_pos[r-1]].len == r; } if( k>1 && i-d>=0){ unko += dp_[i-d]; } dp[j] += unko; if( i-d>=0 ){ dp_[i-d] = unko; } } } // eprintln(dp); // eprintln(dp_); for(int i=1; i 1){ int len = p.t[pos].len; int suf = p.t[pos].suf; int left = i-len-1; if( left >= 0 ){ ans += dp[left]; } pos = suf; } println(ans); return 0; }