#include <bits/stdc++.h>
#define IO_OP std::ios::sync_with_stdio(0); std::cin.tie(0);
#define F first
#define S second
#define V vector
#define PB push_back
#define MP make_pair
#define EB emplace_back
#define ALL(v) (v).begin(), (v).end()
using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef V<int> vi;
string _reset = "\u001b[0m", _yellow = "\u001b[33m", _bold = "\u001b[1m";
void DBG() { cerr << "]" << _reset << endl; }
template<class H, class...T> void DBG(H h, T ...t) {
cerr << to_string(h);
if(sizeof ...(t)) cerr << ", ";
DBG(t...);
}
#ifdef CHEISSMART
#define debug(...) cerr << _yellow << _bold << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define debug(...)
#endif
const int INF = 1e9 + 7, N = 5e5 + 7;
ll diff[N];
signed main()
{
IO_OP;
int n;
cin >> n;
priority_queue<ll> pq;
pq.push(0);
ll lst = 0;
for(int i = 1; i <= n; i++) {
int a, b;
cin >> a >> b;
diff[i] = diff[i - 1] + b - a;
ll x = -diff[i];
if(x < 0) {
lst += pq.top() - x;
pq.pop();
if(pq.empty())
pq.push(0);
} else {
pq.push(x);
if(pq.top() > x) {
lst += pq.top() - x;
pq.pop();
pq.push(x);
}
}
}
assert(diff[n] <= 0);
while(pq.size() && pq.top() > -diff[n]) {
lst += pq.top() - (-diff[n]);
pq.pop();
}
cout << lst << '\n';
}
