/*#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("O3")
#pragma GCC target ("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")*/

#include<bits/stdc++.h>

#define sz(v) (int)v.size()
#define ll long long
#define pb push_back
#define x first
#define y second
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define nl "\n"

using namespace std;
using pii = pair<int, int>;

const int N = (int)3e5 + 7; // make sure this is right
const int M = (int)15e6 + 7;
const int inf = (int)1e9 + 7;
const ll INF = (ll)3e18 + 7;
const ll MOD = (ll)998244353; // make sure this is right

pii dir[] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};

int n, a[N], mx1[N], mx2[N], mn1[N], mn2[N];
vector<int> pos[3 * N];

int get(int i, int x) {
    int l = 1, r = sz(pos[x]), res = 0;
    while(l <= r) {
        int mid = (l + r) >> 1;
        if(pos[x][mid - 1] <= i) {
            res = mid;
            l = mid + 1;
        } else
            r = mid - 1;
    }
    return res;
}

int get(int l, int r, int x) {
    if(l > r) return 0;
    return max(0, get(r, x + n) - get(l - 1, x + n));
}

ll f(int l, int r) {
    if(l == r) return 1;

    int mid = (l + r) >> 1;
    ll res = f(l, mid) + f(mid + 1, r);
    mx1[mid] = mx2[mid + 1] = -inf;
    mn1[mid] = mn2[mid + 1] = inf;
    for(int i = mid + 1; i <= r; ++i) {
        mx1[i] = max(mx1[i - 1], a[i]);
        mn1[i] = min(mn1[i - 1], a[i]);
    }
    for(int i = mid; i >= l; --i) {
        mn2[i] = min(mn2[i + 1], a[i]);
        mx2[i] = max(mx2[i + 1], a[i]);
    }
    int j = mid + 1;
    map<int, int> cnt;
    for(int i = mid + 1; i <= r; ++i) {
        while(j > l && mx2[j - 1] <= mx1[i] && mn2[j - 1] >= mn1[j]) {
            j--;
            cnt[j]++;
        }
        if(i - mx1[i] + mn1[i] >= l && i - mx1[i] + mn1[i] <= mid) res += cnt[i - mx1[i] + mn1[i]];
    }
    cnt.clear();
    j = mid;
    for(int i = mid; i >= l; --i) {
        while(j < r && mx1[j + 1] <= mx2[i] && mn1[j + 1] >= mn2[i]) {
            j++;
            cnt[j]++;
        }
        if(mx2[i] - mn2[i] + i >= mid + 1 && mx2[i] - mn2[i] + i <= r) res += cnt[mx2[i] - mn2[i] + i];
    }

    for(int i = l; i <= mid; ++i) {
        pos[i - mn2[i] + n].pb(i);
    }
    int L = mid, R = mid + 1;
    for(int i = mid + 1; i <= r; ++i) {
        while(L >= l && mn2[L] > mn1[i]) {
            L--;
        }
        while(R > l && mx2[R - 1] <= mx1[i]) {
            R--;
        }
        res += get(R, L, i - mx1[i]);
    }
    for(int i = l; i <= mid; ++i) {
        pos[i - mn2[i] + n].clear();
    }
    for(int i = mid + 1; i <= r; ++i) {
        pos[i + mn1[i] + n].pb(i);
    }
    R = mid;
    L = mid + 1;
    for(int i = mid; i >= l; --i) {
        while(R < r && mx1[R + 1] <= mx2[i]) {
            R++;
        }
        while(L <= r && mn1[L] > mn2[i]) {
            L++;
        }
        res += get(L, R, i + mx2[i]);
    }

    for(int i = mid + 1; i <= r; ++i) {
        pos[i + mn1[i] + n].clear();
    }

    return res;
}

void solve() {
    cin >> n;
    for(int i = 1; i <= n; ++i) {
        int x, y;
        cin >> x >> y;
        a[x] = y;
    }
    cout << f(1, n) << nl;
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int test = 1;
    //cin >> test;
    for(int i = 1; i <= test; ++i) {
        //cout << "Case #" << i << ": ";
        solve();
    }
    return 0;
}