#include <bits/stdc++.h>
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif
template <typename T>
struct fenwick {
int n;
vector<T> node;
fenwick(int _n) : n(_n) {
node.resize(n);
}
void add(int x, T v) {
while (x < n) {
node[x] += v;
x |= (x + 1);
}
}
T get(int x) { // [0, x]
T v = 0;
while (x >= 0) {
v += node[x];
x = (x & (x + 1)) - 1;
}
return v;
}
T get(int x, int y) { // [x, y]
return (get(y) - (x ? get(x - 1) : 0));
}
int lower_bound(T v) {
int x = 0;
int h = 1;
while (n >= (h << 1)) {
h <<= 1;
}
for (int k = h; k > 0; k >>= 1) {
if (x + k <= n && node[x + k - 1] < v) {
v -= node[x + k - 1];
x += k;
}
}
return x;
}
};
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
const int m = (int) 1e5 + 10;
vector<int> a(m);
for (int i = 0; i < n; i++) {
int h, k;
cin >> h >> k;
a[h]--;
a[h - k]++;
}
for (int i = 0; i < m - 1; i++) {
a[i + 1] += a[i];
}
fenwick<int> cnt(m);
fenwick<long long> sum(m);
for (int i = m - 1; i >= 0; i--) {
int lo = a[i] - 1;
int hi = m - 1;
while (hi - lo > 1) {
int mid = (hi + lo) / 2;
long long t = sum.get(mid, m - 1) - cnt.get(mid, m - 1) * 1LL * mid;
if (t <= mid - a[i]) {
hi = mid;
} else {
lo = mid;
}
}
int c = cnt.get(m - 1);
int t = (int) (sum.get(hi, m - 1) - cnt.get(hi, m - 1) * 1LL * hi);
a[i] += t;
while (c != 0 && cnt.lower_bound(c) > hi) {
int pos = cnt.lower_bound(c);
int d = cnt.get(pos, pos);
sum.add(pos, -1LL * pos * d);
cnt.add(pos, -d);
sum.add(hi, 1LL * hi * d);
cnt.add(hi, d);
}
if (hi) {
int d = hi - a[i];
sum.add(hi, -d * 1LL * hi);
sum.add(hi - 1, d * 1LL * lo);
cnt.add(hi, -d);
cnt.add(hi - 1, d);
a[i] = hi;
}
cnt.add(a[i], 1);
sum.add(a[i], a[i]);
}
long long ans = 0;
for (int i = 2; i < m; i++) {
ans += 1LL * cnt.get(i, i) * i * (i - 1) / 2;
}
cout << ans << '\n';
return 0;
}
