#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define maxn 100005
#define file
#define debug(x) cerr << #x << " = " << x << '\n'
int n, sz;
pair<int, int> p[maxn];
struct node {
ll sum, lz, mi;
}t[maxn * 4];
void push (int id, int l, int r) {
if (t[id].lz != 0) {
int mid = (l + r) >> 1;
t[id * 2].sum += (mid - l + 1) * t[id].lz;
t[id * 2 + 1].sum += (r - mid) * t[id].lz;
t[id * 2].mi += t[id].lz;
t[id * 2 + 1].mi += t[id].lz;
t[id * 2].lz += t[id].lz;
t[id * 2 + 1].lz += t[id].lz;
}
t[id].lz = 0;
}
void update (int id, int l, int r, int u, int v) {
if (u > r || l > v) return ;
if (u <= l && r <= v) {
t[id].sum += (r - l + 1);
t[id].lz += 1;
t[id].mi += 1;
return ;
}
int mid = (l + r) >> 1;
push (id, l, r);
update (id * 2, l, mid, u, v);
update (id * 2 + 1, mid + 1, r, u, v);
t[id].sum = t[id * 2].sum + t[id * 2 + 1].sum;
t[id].mi = min (t[id * 2].mi, t[id * 2 + 1].mi);
}
int getpos (int id, int l, int r, int v, int x) {
if (l > v || t[id].mi > x) return -1;
if (l == r) return l;
int mid = (l + r) >> 1;
push (id, l, r);
int res = -1;
if (t[id * 2].mi <= x) res = getpos (id * 2, l, mid, v, x);
if (res == -1) res = getpos (id * 2 + 1, mid + 1, r, v, x);
return res;
}
ll getsum (int id, int l, int r, int u, int v) {
if (u > r || l > v) return 0;
if (u <= l && r <= v) return t[id].sum;
int mid = (l + r) >> 1;
push (id, l, r);
return getsum (id * 2, l, mid, u, v) + getsum (id * 2 + 1, mid + 1, r, u, v);
}
void read() {
cin >> n;
for (int i = 1; i <= n; i++) cin >> p[i].first >> p[i].second, sz = max (sz, p[i].first);
}
void solve() {
sort (p + 1, p + n + 1);
ll ans = 0;
for (int i = 1; i <= n; i++) {
int h = p[i].first, k = p[i].second;
int r = h, l = r - k + 1;
ll val_l = getsum (1, 1, sz, l, l), val_r = getsum (1, 1, sz, r, r);
ll cur = 0, len = r - l + 1;
if (val_l != val_r) {
int pos = getpos (1, 1, sz, r, val_l - 1);
cur += getsum (1, 1, sz, pos, r);
update (1, 1, sz, pos, r);
len -= r - pos + 1;
}
if (len > 0) {
int pos = getpos (1, 1, sz, r, val_l);
cur += getsum (1, 1, sz, pos, pos + len - 1);
update (1, 1, sz, pos, pos + len - 1);
}
ans += cur;
}
cout << ans;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);cout.tie(0);
if (fopen(file".INP","r")) {
freopen(file".INP","r",stdin);
freopen(file".OUT","w",stdout);
}
read();
solve();
return 0;
}
