BOJ-2460

#include <iostream>

using namespace std;

int main() {
    int a, b;
    int total = 0, big = 0;
    for (int i = 1; i <= 9; i++) {
        cin >> a >> b;
        total += -a + b;
        if (total > big) big = total;
    }
    cout << big;
}