#pragma GCC optimize ("O3") #include "bits/stdc++.h" using namespace std; using ll = long long int; #define debugos cout #define debug(v) {printf("L%d %s > ",__LINE__,#v);debugos<<(v)< ",__LINE__,#v);for(auto e:(v)){debugos< ",__LINE__,#m);for(int x=0;x<(w);x++){debugos<<(m)[x]<<" ";}debugos<\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){debugos<<(m)[y][x]<<" ";}debugos<::type>::type cnt=0;(cnt)<(l);++(cnt)) #define rrepeat(cnt,l) for(auto cnt=(l)-1;0<=(cnt);--(cnt)) #define iterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);++(cnt)) #define diterate(cnt,b,e) for(auto cnt=(b);(cnt)!=(e);--(cnt)) const ll MD = 1000000007ll; const long double PI = 3.1415926535897932384626433832795L; inline void assert_call(bool assertion, function f) { if (!assertion) { cerr << "assertion fault:" << endl; f(); abort(); } } template inline ostream& operator <<(ostream &o, const pair p) { o << '(' << p.first << ':' << p.second << ')'; return o; } template inline ostream& _ostream_vecprint(ostream& os, const Vec& a) { os << '['; for (const auto& e : a) os << ' ' << e << ' '; os << ']'; return os; } template inline ostream& operator<<(ostream& o, const vector& v) { return _ostream_vecprint(o, v); } template inline ostream& operator<<(ostream& o, const array& v) { return _ostream_vecprint(o, v); } template inline T& maxset(T& to, const T& val) { return to = max(to, val); } template inline T& minset(T& to, const T& val) { return to = min(to, val); } void bye(string s, int code = 0) { cout << s << endl; exit(code); } mt19937_64 randdev(8901016); template inline T rand(T l, T h) { return uniform_int_distribution(l, h)(randdev); } template<> inline double rand(double l, double h) { return uniform_real_distribution(l, h)(randdev); } template<> inline float rand(float l, float h) { return uniform_real_distribution(l, h)(randdev); } #if defined(_WIN32) || defined(_WIN64) #define getchar_unlocked _getchar_nolock #define putchar_unlocked _putchar_nolock #elif defined(__GNUC__) #else #define getchar_unlocked getchar #define putchar_unlocked putchar #endif namespace { #define isvisiblechar(c) (0x21<=(c)&&(c)<=0x7E) class MaiScanner { public: template void input_integer(T& var) noexcept { var = 0; T sign = 1; int cc = getchar_unlocked(); for (; cc < '0' || '9' < cc; cc = getchar_unlocked()) if (cc == '-') sign = -1; for (; '0' <= cc && cc <= '9'; cc = getchar_unlocked()) var = (var << 3) + (var << 1) + cc - '0'; var = var * sign; } inline int c() noexcept { return getchar_unlocked(); } inline MaiScanner& operator>>(int& var) noexcept { input_integer(var); return *this; } inline MaiScanner& operator>>(long long& var) noexcept { input_integer(var); return *this; } inline MaiScanner& operator>>(string& var) { int cc = getchar_unlocked(); for (; !isvisiblechar(cc); cc = getchar_unlocked()); for (; isvisiblechar(cc); cc = getchar_unlocked()) var.push_back(cc); return *this; } template void in(IT begin, IT end) { for (auto it = begin; it != end; ++it) *this >> *it; } }; class MaiPrinter { public: template void output_integer(T var) noexcept { if (var == 0) { putchar_unlocked('0'); return; } if (var < 0) putchar_unlocked('-'), var = -var; char stack[32]; int stack_p = 0; while (var) stack[stack_p++] = '0' + (var % 10), var /= 10; while (stack_p) putchar_unlocked(stack[--stack_p]); } inline MaiPrinter& operator<<(char c) noexcept { putchar_unlocked(c); return *this; } inline MaiPrinter& operator<<(int var) noexcept { output_integer(var); return *this; } inline MaiPrinter& operator<<(long long var) noexcept { output_integer(var); return *this; } inline MaiPrinter& operator<<(char* str_p) noexcept { while (*str_p) putchar_unlocked(*(str_p++)); return *this; } inline MaiPrinter& operator<<(const string& str) { const char* p = str.c_str(); const char* l = p + str.size(); while (p < l) putchar_unlocked(*p++); return *this; } template void join(IT begin, IT end, char sep = ' ') { for (bool b = 0; begin != end; ++begin, b = 1) b ? *this << sep << *begin : *this << *begin; } }; } MaiScanner scanner; MaiPrinter printer; template class Bitree { public: int size_; vector data_; Bitree(int size_) :size_(size_), data_(size_ + 1) {} // 1..rの範囲の値の和を求める. T sum(int r) { T s = 0; while (r) { s += data_[r]; r -= r & -r; // r&-r と書くことで最下のビットを得る } return s; } // l..rの範囲の値の和を求める inline T sum(int l, int r) { return sum(r) - sum(l - 1); } // idxの要素の値をval増やす void add(int idx, T val) { while (idx <= size_) { data_[idx] += val; idx += idx & -idx; } } }; int N, M; vector> edges; int main() { scanner >> M >> N; edges.reserve(M); repeat(i, M) { int a, b; scanner >> a >> b; if (a > b) swap(a, b); edges.emplace_back(a, b); } sort(ALL(edges)); Bitree bit(N+2); ll ans = 0; repeat(i, M) { int a, b; a = edges[i].first; b = edges[i].second; ++a; ++b; int ha = bit.sum(a); int hb = bit.sum(b); ans += abs(ha - hb); bit.add(a, 1); bit.add(b, -1); } printer << ans << '\n'; return 0; }