#include <bits/stdc++.h>
using namespace std;
int inf;
const double eps = 1e-8;
const double pi = acos(-1.0);
template <class T, class T2>
int chkmin(T &a, T2 b) {
  return a > b ? a = b, 1 : 0;
}
template <class T, class T2>
int chkmax(T &a, T2 b) {
  return a < b ? a = b, 1 : 0;
}
template <class T>
T sqr(T a) {
  return a * a;
}
template <class T, class T2>
T mmin(T a, T2 b) {
  return a < b ? a : b;
}
template <class T, class T2>
T mmax(T a, T2 b) {
  return a > b ? a : b;
}
template <class T>
T aabs(T a) {
  return a < 0 ? -a : a;
}
template <class T>
int dcmp(T a, T b) {
  return a > b;
}
template <int *a>
int cmp_a(int first, int second) {
  return a[first] < a[second];
}
template <class T>
bool sort2(T &a, T &b) {
  return a > b ? swap(a, b), 1 : 0;
}
struct __INIT__ {
  __INIT__() {
    fill((unsigned char *)&inf, (unsigned char *)&inf + sizeof(inf), 0x3f);
  }
} __INIT___;
namespace io {
const int SIZE = (1 << 21) + 1;
char ibuf[SIZE], *iS, *iT, obuf[SIZE], *oS = obuf, *oT = oS + SIZE - 1, c,
                                       qu[55];
int f, qr;
inline void flush() {
  fwrite(obuf, 1, oS - obuf, stdout);
  oS = obuf;
}
inline void putc(char first) {
  *oS++ = first;
  if (oS == oT) flush();
}
template <typename A>
inline bool read(A &first) {
  for (f = 1, c = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                              (iS == iT ? EOF : *iS++))
                            : *iS++);
       c < '0' || c > '9';
       c = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    if (c == '-')
      f = -1;
    else if (c == EOF)
      return 0;
  for (first = 0; c <= '9' && c >= '0';
       c = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    first = first * 10 + (c & 15);
  first *= f;
  return 1;
}
inline bool read(char &first) {
  while ((first = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                               (iS == iT ? EOF : *iS++))
                            : *iS++)) == ' ' ||
         first == '\n' || first == '\r')
    ;
  return first != EOF;
}
inline bool read(char *first) {
  while ((*first = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                                (iS == iT ? EOF : *iS++))
                             : *iS++)) == '\n' ||
         *first == ' ' || *first == '\r')
    ;
  if (*first == EOF) return 0;
  while (!(*first == '\n' || *first == ' ' || *first == '\r' || *first == EOF))
    *(++first) = (iS == iT ? (iT = (iS = ibuf) + fread(ibuf, 1, SIZE, stdin),
                              (iS == iT ? EOF : *iS++))
                           : *iS++);
  *first = 0;
  return 1;
}
template <typename A, typename... B>
inline bool read(A &first, B &...second) {
  return read(first) && read(second...);
}
template <typename A>
inline bool write(A first) {
  if (!first) putc('0');
  if (first < 0) putc('-'), first = -first;
  while (first) qu[++qr] = first % 10 + '0', first /= 10;
  while (qr) putc(qu[qr--]);
  return 0;
}
inline bool write(char first) {
  putc(first);
  return 0;
}
inline bool write(const char *first) {
  while (*first) {
    putc(*first);
    ++first;
  }
  return 0;
}
inline bool write(char *first) {
  while (*first) {
    putc(*first);
    ++first;
  }
  return 0;
}
template <typename A, typename... B>
inline bool write(A first, B... second) {
  return write(first) || write(second...);
}
struct Flusher_ {
  ~Flusher_() { flush(); }
} io_flusher_;
}  // namespace io
using io ::putc;
using io ::read;
using io ::write;
int a[300005], b[300005];
pair<int, int> merge(pair<int, int> a, pair<int, int> b) {
  int first = mmin(a.first, b.first);
  return {first, (a.first == first ? a.second : 0) +
                     (b.first == first ? b.second : 0)};
}
struct smt {
  int ls, rs;
  pair<int, int> mn;
  int tag;
  smt *l, *r;
  smt() {}
  smt(int, int);
  void put_tag(int first) {
    tag += first;
    mn.first += first;
  }
  void push_down() {
    if (tag) {
      l->put_tag(tag);
      r->put_tag(tag);
      tag = 0;
    }
  }
  void set(int first, int second) {
    if (ls == rs) {
      mn = {second, 1};
      return;
    }
    push_down();
    if (first <= l->rs)
      l->set(first, second);
    else
      r->set(first, second);
    mn = merge(l->mn, r->mn);
  }
  void add(int la, int ra, int first) {
    if (la <= ls && rs <= ra) {
      put_tag(first);
      return;
    }
    push_down();
    if (la <= l->rs) l->add(la, ra, first);
    if (r->ls <= ra) r->add(la, ra, first);
    mn = merge(l->mn, r->mn);
  }
};
smt *rt, node[600005], *at = node;
smt *newsmt(int la, int ra) {
  smt *rt = at;
  ++at;
  *rt = smt(la, ra);
  return rt;
}
smt::smt(int la, int ra) {
  ls = la;
  rs = ra;
  mn = {inf, rs - ls + 1};
  tag = 0;
  if (ls == rs) {
    l = r = 0;
    return;
  }
  int mid = (ls + rs) >> 1;
  l = newsmt(ls, mid);
  r = newsmt(mid + 1, rs);
}
signed main() {
  int n, first, second;
  read(n);
  for (int i = 1; i <= n; ++i) {
    read(first, second);
    a[first] = second;
    b[second] = first;
  }
  rt = newsmt(1, n);
  b[0] = b[n + 1] = inf;
  long long ans = 0;
  for (int i = 1; i <= n; ++i) {
    rt->set(i, 0);
    rt->add(1, i, 1);
    if (b[a[i] - 1] < i) rt->add(1, b[a[i] - 1], -1);
    if (b[a[i] + 1] < i) rt->add(1, b[a[i] + 1], -1);
    ans += rt->mn.second;
  }
  write(ans, '\n');
  return 0;
}
