//https://oj.uz/problem/view/LMIO19_bulves
#include<iostream>
#include<vector>
#include<set>
#include<map>
#include<iomanip>
#include <cassert>
#include<algorithm>
#include<queue>
#include <array>
#include <bitset>
#include<cstring>
using namespace std;
#define int long long
#define pii pair<int,int>
int INF = 1e18;
int a[500001];
int n;
void ez(){
int cur = 0;
int ans = 0;
for(int i = 1; i <= n; ++i){
cur += a[i];
ans += abs(cur);
}
cout << ans << "\n";
}
int dp[10]; int dp2[10];
const int lol = 1;
void onedp(){
vector<int>psums(n + 1, 0);
for(int i = 1; i <= n; ++i){
psums[i] = psums[i - 1] + a[i];
}
//vector<vector<int>>dp(n + 2, vector<int>(2, INF)); //min cost to reach this state
//state: from 1...i-1 is all 0, if j==1 then it has the total prefix sums here, otherwise, it has one less than the total prefix sums, (didn't transfer one)
memset(dp, 0x3f, sizeof(dp));
memset(dp2, 0x3f, sizeof(dp2));
dp[0] = 0;
for(int i = 1; i <= n; ++i){
for(int j = 0; j <= lol; ++j){
//if the psums is negative, you must transfer it all out (def not optimal to just drag it here)
dp2[j] = min(dp2[j], dp[j] + abs(psums[i] - j));
for(int keep = 0; keep <= lol - j; ++keep){
dp2[keep + j] = min(dp2[j + keep], dp[j] + abs(psums[i] - j - keep));
}
}
/*
for(int j = 0; j <= 10; ++j){
if(dp[j] >= INF){
cout << "inf "; continue;
}
cout << dp[j] << " ";
}
cout << endl;
*/
swap(dp, dp2);
memset(dp2, 0x3f, sizeof(dp2));
}
int ans = INF;
for(int i = 0; i < 3; ++i){
ans = min(ans, dp[i]);
}
cout << ans << "\n";
}
int32_t main(){
cin.tie(0)->sync_with_stdio(0);
cin >> n;
int sumA = 0;
for(int i = 1; i <= n; ++i){
int x, y; cin >> x >> y;
a[i] = x - y;
sumA += x - y;
}
if(sumA == 0){
ez();
} else{
onedp();
}
}
