#include <iostream>
#include <algorithm>
using namespace std;

int main(){
	int n;
	cin >> n;
	int64_t a[n], b[n];
	for(int i = 0; i < n; i++) cin >> a[i] >> b[i];
	int64_t chi_a = 0, chi_b = 0;
	for(int i = 0; i < n; i++){
		int64_t diff_a = abs((chi_a + a[i]) - chi_b), diff_b = abs(chi_a - (chi_b + b[i]));
		if(diff_a < diff_b) chi_a += a[i];
		else chi_b += b[i];
	}
	cout << abs(chi_a - chi_b) << endl;
}