import java.io.*;
import java.util.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        TreeSet<Long> ev = new TreeSet<>();
        TreeSet<Long> od = new TreeSet<>();
        ev.add(0L);
        od.add(0L);
        long total = 0;
        for (int i = 0; i < n; i++) {
            long a = sc.nextLong();
            long b = sc.nextLong();
            total += a;
            b += a;
            TreeSet<Long> current;
            if (i % 2 == 0) {
                current = ev;
            } else {
                current = od;
            }
            Long key = Long.MAX_VALUE;
            while ((key = current.lower(key)) != null) {
                current.add(key + b);
            }
        }
        od.add(Long.MIN_VALUE / 2);
        od.add(Long.MAX_VALUE / 2);
        long ans = Long.MAX_VALUE;
        for (Long x : ev) {
            long target = total - x;
            ans = Math.min(ans, target - od.floor(target));
            ans = Math.min(ans, od.ceiling(target) - target);
        }
        System.out.println(ans);
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}