#include <bits/stdc++.h>
using namespace std;
namespace io {
const int SI = 1 << 21 | 1;
char IB[SI], *IS, *IT, OB[SI], *OS = OB, *OT = OS + SI - 1, c, ch[100];
int f, t;
inline void flush() { fwrite(OB, 1, OS - OB, stdout), OS = OB; }
inline void pc(char x) {
  *OS++ = x;
  if (OS == OT) flush();
}
template <class I>
inline void rd(I &x) {
  for (f = 1, c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                              IS == IT ? EOF : *IS++)
                            : *IS++);
       c < '0' || c > '9';
       c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                       IS == IT ? EOF : *IS++)
                     : *IS++))
    if (c == '-') f = -1;
  for (x = 0; c >= '0' && c <= '9'; x = (x << 3) + (x << 1) + (c & 15),
      c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                      IS == IT ? EOF : *IS++)
                    : *IS++))
    ;
  x *= f;
}
inline void rds(char *s, int &x) {
  for (c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                       IS == IT ? EOF : *IS++)
                     : *IS++);
       c < 33 || c > 126;
       c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                       IS == IT ? EOF : *IS++)
                     : *IS++))
    ;
  for (x = 0; c >= 33 && c <= 126;
       s[++x] = c, c = (IS == IT ? (IT = (IS = IB) + fread(IB, 1, SI, stdin),
                                   IS == IT ? EOF : *IS++)
                                 : *IS++))
    ;
  s[x + 1] = '\0';
}
template <class I>
inline void print(I x, char k = '\n') {
  if (!x) pc('0');
  if (x < 0) pc('-'), x = -x;
  while (x) ch[++t] = x % 10 + '0', x /= 10;
  while (t) pc(ch[t--]);
  pc(k);
}
inline void prints(string s) {
  int x = s.length();
  while (t < x) pc(s[t++]);
  pc('\n'), t = 0;
}
struct Flush {
  ~Flush() { flush(); }
} flusher;
}  // namespace io
using io::print;
using io::prints;
using io::rd;
using io::rds;
const int N = 3e5 + 7;
int n, a[N], sx[N], tx, sn[N], tn;
map<int, int> p;
struct T {
  int l, r, x, c, z;
} t[N << 2];
long long ans;
void build(int p, int l, int r) {
  t[p].l = l, t[p].r = r, t[p].c = r - l + 1;
  if (l == r) return;
  build((p << 1), l, ((t[p].l + t[p].r) >> 1)),
      build(((p << 1) | 1), ((t[p].l + t[p].r) >> 1) + 1, r);
}
inline void add(int p, int x) { t[p].x += x, t[p].z += x; }
void upd(int p, int l, int r, int x) {
  if (t[p].l >= l && t[p].r <= r) return add(p, x);
  if (t[p].z) add((p << 1), t[p].z), add(((p << 1) | 1), t[p].z), t[p].z = 0;
  if (l <= ((t[p].l + t[p].r) >> 1)) upd((p << 1), l, r, x);
  if (r > ((t[p].l + t[p].r) >> 1)) upd(((p << 1) | 1), l, r, x);
  t[p].x = min(t[(p << 1)].x, t[((p << 1) | 1)].x);
  t[p].c = (t[(p << 1)].x == t[p].x ? t[(p << 1)].c : 0) +
           (t[((p << 1) | 1)].x == t[p].x ? t[((p << 1) | 1)].c : 0);
}
int main() {
  rd(n);
  for (int i = 1, x, y; i <= n; i++) rd(x), rd(y), a[x] = y;
  build(1, 1, n);
  for (int i = 1; i <= n; i++) {
    while (tx && a[sx[tx]] < a[i])
      upd(1, sx[tx - 1] + 1, sx[tx], -a[sx[tx]]), --tx;
    while (tn && a[sn[tn]] > a[i])
      upd(1, sn[tn - 1] + 1, sn[tn], a[sn[tn]]), --tn;
    upd(1, p[a[i]] + 1, i, -1), p[a[i]] = sx[++tx] = sn[++tn] = i;
    upd(1, sx[tx - 1] + 1, i, a[i]), upd(1, sn[tn - 1] + 1, i, -a[i]);
    ans += t[1].c;
  }
  print(ans);
  return 0;
}
