#include<iostream>
#include<cmath>
#include<cstring>
#include<cassert>
#include<string>
#include<queue>
#include<deque>
#include<stack>
#include<algorithm>
#include<unordered_map>
#include<map>
#include<vector>
#include<set>
#include<unordered_set>
#include<bitset>
#include<climits>
#include<numeric>
#include<functional>
#include<iomanip>
#ifdef YJL
#include<debug.h>
#else
#define debug(args...)0
#define debug_n(a,n)0
#endif
#define ALL(a) a.begin(),a.end()
using namespace std;
using ll=long long;
constexpr ll inf = numeric_limits<ll>::max()/2;
struct slope_trick_concave {// 凹折线函数
priority_queue<ll> ql;
priority_queue<ll,vector<ll>,greater<>> qr;
ll tagl,tagr;// 左右堆中斜率改变点的懒标记
ll height;// 最低点高度
slope_trick_concave(): tagl(0), tagr(0), height(0) {
ql.push(-inf);
qr.push(inf);
}
ll get_left() {
return ql.top()+tagl;
}
ll get_right() {
return qr.top()+tagr;
}
// f(x) = g(x) + |x-c|
void add(ll c) {
ll xl=get_left();
ll xr=get_right();
if(xl <= c && c <= xr) {
ql.push(c-tagl);
qr.push(c-tagr);
}else if(c < xl) {
height+=xl-c;
qr.push(xl-tagr);
ql.pop();
ql.push(c-tagl);
ql.push(c-tagl);
}else {
height+=c-xr;
ql.push(xr-tagl);
qr.pop();
qr.push(c-tagr);
qr.push(c-tagr);
}
}
// g(x) = min_{y=x+low, x+high} f(y)
void range_min(ll low, ll high) {
tagl-=high;
tagr-=low;
}
// g(x) = min_{y=-inf, x} f(y)
void pref_min() {
tagr=0;
while(qr.size()>1)
qr.pop();
}
};
int main() {
ios::sync_with_stdio(0), cin.tie(0);
int n;
cin>>n;
vector<ll> a(n),b(n);
for(int i=0; i<n; ++i) {
cin>>a[i];
cin>>b[i];
a[i]-=b[i];
if(i) a[i]+=a[i-1];
}
// for(int i=0; i<n; ++i) {
// }
slope_trick_concave sp;
ll ans=0;
for(int i=0; i<n; ++i) {
if(a[i]<0) {
ans-=a[i];
a[i]=0;
}
if(a[i]>a[n-1]) {
ans+=a[i]-a[n-1];
a[i]=a[n-1];
}
sp.add(a[i]);
sp.pref_min();
}
cout<<ans+sp.height;
return 0;
}
/*
a[i]++, a[i+1]--
前缀和
a[i]++
最后
0<=a[0]<=..<=a[n-1]
*/
