# coding: utf-8
import array, bisect, collections, copy, heapq, itertools, math, random, re, string, sys, time
sys.setrecursionlimit(10 ** 7)
INF = 10 ** 20
MOD = 10 ** 9 + 7


def II(): return int(input())
def ILI(): return list(map(int, input().split()))
def IAI(LINE): return [ILI() for __ in range(LINE)]
def IDI(): return {key: value for key, value in ILI()}


def read():
    n = II()
    A, B = [], []
    for __ in range(n):
        a, b = ILI()
        A.append(a)
        B.append(b)
    return n, A, B


def solve(n, A, B):
    now_a = 0
    now_b = 0
    for a, b in zip(A, B):
        next_dif_a = abs(now_a + a - now_b)
        next_dif_b = abs(now_b + b - now_a)
        if next_dif_a >= next_dif_b:
            now_b += b
        else:
            now_a += a

    ans = abs(now_a - now_b)
    return ans


def main():
    params = read()
    print(solve(*params))


if __name__ == "__main__":
    main()