#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define inf INT_MAX
#define fr(i,l,r) for (i=(l); i<=(r); i++)
#define rfr(i,l,r) for (i=(l); i>=(r); i--)
template<typename T>inline void read(T &n){
    T w=1; n=0; char ch=getchar();
    while (!isdigit(ch) && ch!=EOF){ if (ch=='-') w=-1; ch=getchar(); }
    while (isdigit(ch) && ch!=EOF){ n=(n<<3)+(n<<1)+(ch&15); ch=getchar(); }
    n*=w;
}
template<typename T>inline void write(T x){
    if (x==0){ putchar('0'); return ; }
    T tmp;
    if (x>0) tmp=x;
    else tmp=-x;
    if (x<0) putchar('-');
    char F[105];
    long long cnt=0;
    while (tmp){
        F[++cnt]=tmp%10+48;
        tmp/=10;
    }
    while (cnt) putchar(F[cnt--]);
}
#define Min(x,y) x = min(x,y)
#define Max(x,y) x = max(x,y)
//基础配置=================================================================================
const ll N = 505;
ll n,m;
ll a[N][N], b[N][N];
ll f[N][N], g[N][N];
ll calc(ll l,ll r,ll k){
    ll x = a[l][k], y = b[l][k], xx = a[k+1][r], yy = b[k+1][r];
    ll ans = max(x,xx) - min(x,xx) + max(y,yy) - min(y,yy);
    // printf("( %lld , %lld ) , ( %lld , %lld ) \n",x,y,xx,yy);
    // printf("calc %lld %lld %lld = %lld\n",l,r,k,ans);
    return ans;
}
int main(){
	// freopen("a.in","r",stdin);
//	freopen(".out","w",stdout);
    ll i,j,k;
    read(n);
    memset(a,0x0f,sizeof(a)), memset(b,0x0f,sizeof(b));
    a[0][0] = b[0][0] = 0;
    fr(i,1,n) read(a[i][i]), read(b[i][i]);
    rfr(i,n,0)
        fr(j,i+1,n){
            a[i][j] = min(a[i][i],a[i+1][j]);
            b[i][j] = min(b[i][i],b[i+1][j]);
        }
    memset(f,0x0f,sizeof(f));
    memset(g,0x0f,sizeof(g));
    rfr(i,n,0){
        // printf("\n\n\ni = %lld\n",i);
        ll r = i;
        fr(j,i+1,n){
            if (a[j][j]>=a[i][i] && b[j][j]>=b[i][i]) r = j;
            else break;
        }
        // printf("r = %lld\n",r);
        f[i][i] = 0;
        fr(j,i+1,r){
            f[i][j] = g[i+1][j] + calc(i,j,i);
            // printf("\n j = %lld\n",j);
            // fr(k,i,j-1){
                // Min( f[i][j] , f[i][k] + g[k+1][j] + calc(i,j,k) );
                // printf("%lld ~ %lld , %lld : %lld + %lld + %lld\n",i,j,k,f[i][k] , g[k+1][j] , calc(i,j,k));
            // }
            // printf("f[%lld][%lld] = %lld\n",i,j,f[i][j]);
        }
        // printf("\n");
        fr(j,i,n){
            g[i][j] = f[i][j];
            fr(k,i,min(r,j-1))
                Min( g[i][j] , f[i][k] + g[k+1][j] + calc(i,j,k) );
            // printf("g[%lld][%lld] = %lld\n",i,j,g[i][j]);
        }
        // fr(j,i,r) printf("f[%lld][%lld] = %lld\n",i,j,f[i][j]);
    }
    ll ans = f[0][n]; write(ans);
    return 0;
}
//g++ a.cpp -o a -Wall -Wl,--stack=512000000 -std=c++11 -O2