#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll N = 5e5+5, MAX = 3e4+5, ZERO = 3e4, INF = 1e18;
ll n, delta;
ll val[N], pref[N];
void read() {
cin >> n;
for(int i = 1; i <= n; i++) {
ll a, b; cin >> a >> b;
val[i] = a - b;
}
}
void solve() {
pref[0] = 0;
for(int i = 1; i <= n; i++) {
pref[i] = pref[i-1] + val[i];
}
delta = pref[n];
ll ans = 0, x;
priority_queue<ll> pq;
pq.push(0);
for(int i = 1; i <= n; i++) {
x = pref[i];
if(x < 0) {
ans += -x;
x = 0;
} else if(x > delta) {
ans += x - delta;
x = delta;
}
pq.push(x);
pq.push(x);
ans += pq.top() - x;
pq.pop();
}
cout << ans << '\n';
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
read();
solve();
return 0;
}
