#include<cstdio>
#include<algorithm>
#include<queue>
#include<vector>
using std::priority_queue;
using std::vector;
using std::less;
using std::greater;
#define r register
inline bool isd(r char ch)
{
	return ch<='9'&&ch>='0';
}
template<class temp>
inline temp F()
{
	r temp x=0;
	r bool bo=0;
	r char ch=getchar();
	while(ch!='-'&&!isd(ch))
		ch=getchar();
	(ch=='-')&&(bo=1,ch=getchar());
	x=ch^'0',ch=getchar();
	while(isd(ch))
		x=(x<<1)+(x<<3)+(ch^'0'),ch=getchar();
	bo&&(x=-x);
	return x;
}
int lt[200001],rt[200001];
long long ans,tl,tr,lq,rq;
priority_queue<long long,vector<long long>,less<long long> >L; 
priority_queue<long long,vector<long long>,greater<long long> >R;
int main()
{
    r int n=F<int>();
    for(r int i=1;i<=n;++i)
		lt[i]=F<int>(),rt[i]=F<int>(),lt[i]=rt[i]-lt[i];
    L.push(rt[1]),R.push(rt[1]);
    for(r int i=2;i<=n;++i)
	{
        tl-=lt[i-1],tr+=lt[i];
        lq=L.top()+tl,rq=R.top()+tr;
        if(rt[i]>=lq&&rt[i]<=rq)
			L.push(rt[i]-tl),R.push(rt[i]-tr);
        else
			if(rt[i]>=lq)
            	ans+=rt[i]-rq,R.pop(),L.push(rq-tl),R.push(rt[i]-tr),R.push(rt[i]-tr);
			else
            	ans+=lq-rt[i],L.pop(),R.push(lq-tr),L.push(rt[i]-tl),L.push(rt[i]-tl);
    }
    printf("%lld\n",ans);
}