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

int main(void){
    int n;
    long long a[n+1], b[n+1], sum_a=0,sum_b=0;
    cin >> n;
    for(int i=0; i<n; i++){
        cin >> a[i] >> b[i];
        if(abs( (sum_a + a[i]) - sum_b) <= abs((sum_b+b[i]) - sum_a) ){
            sum_a += a[i];
        }else{
            sum_b += b[i];
        }
    }
    cout << abs(sum_a - sum_b) << endl;
    return 0;
}