#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline bool upmin(T &x, T y) {
  return y < x ? x = y, 1 : 0;
}
template <typename T>
inline bool upmax(T &x, T y) {
  return x < y ? x = y, 1 : 0;
}
const long double eps = 1e-9;
const long double pi = acos(-1);
const int oo = 1 << 30;
const long long loo = 1ll << 62;
const int mods = 1e9 + 7;
const int MAXN = 300005;
const int INF = 0x3f3f3f3f;
namespace FastIO {
constexpr int SIZE = (1 << 21) + 1;
int num = 0, f;
char ibuf[SIZE], obuf[SIZE], que[65], *iS, *iT, *oS = obuf,
                                                *oT = obuf + SIZE - 1, c;
inline void flush() {
  fwrite(obuf, 1, oS - obuf, stdout);
  oS = obuf;
}
inline void putc(char c) {
  *oS++ = c;
  if (oS == oT) flush();
}
inline void getc(char &c) {
  for (c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++);
       c < 'A' || c > 'Z';
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    ;
}
template <class I>
inline void read(I &x) {
  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;
  for (x = 0; c >= '0' && c <= '9';
       c = (iS == iT ? (iT = ((iS = ibuf) + fread(ibuf, 1, SIZE, stdin)),
                       (iS == iT ? EOF : *iS++))
                     : *iS++))
    x = (x << 3) + (x << 1) + (c & 15);
  x *= f;
}
template <class I>
inline void print(I x) {
  if (x < 0) putc('-'), x = -x;
  if (!x) putc('0');
  while (x) que[++num] = x % 10 + 48, x /= 10;
  while (num) putc(que[num--]);
}
struct Flusher_ {
  ~Flusher_() { flush(); }
} io_Flusher_;
}  // namespace FastIO
using FastIO ::print;
using FastIO ::putc;
using FastIO ::read;
int tag[MAXN << 2], mn[MAXN << 2], s[MAXN << 2], stkmx[MAXN], stkmn[MAXN],
    p[MAXN];
void up(int x) {
  mn[x] = min(mn[x << 1], mn[x << 1 | 1]);
  s[x] = (mn[x << 1] == mn[x]) * s[x << 1] +
         (mn[x << 1 | 1] == mn[x]) * s[x << 1 | 1];
}
void down(int x) {
  if (tag[x] == 0) return;
  mn[x << 1] += tag[x], mn[x << 1 | 1] += tag[x];
  tag[x << 1] += tag[x], tag[x << 1 | 1] += tag[x];
  tag[x] = 0;
}
void build(int x, int l, int r) {
  if (l == r) {
    mn[x] = r - l + 1, s[x] = 1;
    return;
  }
  int mid = (l + r) >> 1;
  build(x << 1, l, mid);
  build(x << 1 | 1, mid + 1, r);
  up(x);
}
void update(int x, int l, int r, int L, int R, int y) {
  if (l >= L && r <= R) {
    mn[x] += y, tag[x] += y;
    return;
  }
  down(x);
  int mid = (l + r) >> 1;
  if (R <= mid)
    update(x << 1, l, mid, L, R, y);
  else if (L > mid)
    update(x << 1 | 1, mid + 1, r, L, R, y);
  else
    update(x << 1, l, mid, L, mid, y),
        update(x << 1 | 1, mid + 1, r, mid + 1, R, y);
  up(x);
}
signed main() {
  int n;
  read(n);
  for (int i = 1, x, y; i <= n; ++i) read(x), read(y), p[x] = y;
  build(1, 1, n);
  long long ans = 0;
  for (int i = 1, topmx = 0, topmn = 0; i <= n; ++i) {
    while (topmx && p[stkmx[topmx]] < p[i])
      update(1, 1, n, stkmx[topmx - 1] + 1, stkmx[topmx], -p[stkmx[topmx]]),
          --topmx;
    while (topmn && p[stkmn[topmn]] > p[i])
      update(1, 1, n, stkmn[topmn - 1] + 1, stkmn[topmn], p[stkmn[topmn]]),
          --topmn;
    update(1, 1, n, 1, i, -1);
    update(1, 1, n, stkmx[topmx] + 1, i, p[i]);
    update(1, 1, n, stkmn[topmn] + 1, i, -p[i]);
    ans += s[1];
    stkmx[++topmx] = i;
    stkmn[++topmn] = i;
  }
  print(ans);
  return 0;
}
