#include <bits/stdc++.h>
using namespace std;
int a[300010];
struct _ {
  int val, rpos;
};
vector<_> min_, max_;
int vmin[1200010], cmin[1200010], add[1200010];
void pushup(int rt) {
  if (vmin[rt << 1] == vmin[rt << 1 | 1]) {
    vmin[rt] = vmin[rt << 1];
    cmin[rt] = cmin[rt << 1] + cmin[rt << 1 | 1];
  } else {
    if (vmin[rt << 1] < vmin[rt << 1 | 1]) {
      vmin[rt] = vmin[rt << 1];
      cmin[rt] = cmin[rt << 1];
    } else {
      vmin[rt] = vmin[rt << 1 | 1];
      cmin[rt] = cmin[rt << 1 | 1];
    }
  }
}
void build(int l, int r, int rt) {
  if (l == r) {
    cmin[rt] = 1;
    return;
  }
  int m = l + r >> 1;
  build(l, m, rt << 1);
  build(m + 1, r, rt << 1 | 1);
  pushup(rt);
}
void pushdown(int rt) {
  if (add[rt]) {
    add[rt << 1] += add[rt];
    vmin[rt << 1] += add[rt];
    add[rt << 1 | 1] += add[rt];
    vmin[rt << 1 | 1] += add[rt];
    add[rt] = 0;
    return;
  }
}
void update(int L, int R, int c, int l, int r, int rt) {
  if (L <= l && r <= R) {
    add[rt] += c;
    vmin[rt] += c;
    return;
  }
  int m = l + r >> 1;
  pushdown(rt);
  if (m >= L) update(L, R, c, l, m, rt << 1);
  if (m < R) update(L, R, c, m + 1, r, rt << 1 | 1);
  pushup(rt);
}
struct __ {
  int v, c;
  __ operator+(const __ &ob) const {
    __ rv;
    if (v == ob.v) {
      rv.v = v;
      rv.c = c + ob.c;
    } else {
      if (v < ob.v) {
        rv.v = v;
        rv.c = c;
      } else {
        rv.v = ob.v;
        rv.c = ob.c;
      }
    }
    return rv;
  }
};
__ query(int L, int R, int l, int r, int rt) {
  if (L <= l && r <= R) return (__){vmin[rt], cmin[rt]};
  int m = l + r >> 1;
  pushdown(rt);
  __ ans;
  ans.v = 998244353;
  if (m >= L) ans = ans + query(L, R, l, m, rt << 1);
  if (m < R) ans = ans + query(L, R, m + 1, r, rt << 1 | 1);
  return ans;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  build(1, n, 1);
  int i;
  int x, y;
  for (i = 1; i <= n; ++i) {
    cin >> x >> y;
    a[x] = y;
  }
  min_.push_back((_){-1, 0});
  max_.push_back((_){n + 1, 0});
  long long ans = 0;
  for (i = 1; i <= n; ++i) {
    while (min_.back().val >= a[i]) {
      update(min_[min_.size() - 2].rpos + 1, min_.back().rpos, min_.back().val,
             1, n, 1);
      min_.pop_back();
    }
    update(min_.back().rpos + 1, i, -a[i], 1, n, 1);
    min_.push_back((_){a[i], i});
    while (max_.back().val <= a[i]) {
      update(max_[max_.size() - 2].rpos + 1, max_.back().rpos, -max_.back().val,
             1, n, 1);
      max_.pop_back();
    }
    update(max_.back().rpos + 1, i, a[i], 1, n, 1);
    max_.push_back((_){a[i], i});
    update(1, i, -1, 1, n, 1);
    ans += query(1, i, 1, n, 1).c;
  }
  cout << ans << '\n';
  return 0;
}
