백준 2455번 C++

#include <iostream>
#include <algorithm>

using namespace std;

int main(void) {
	int current=0, maxnum = -1;

	for (int i = 0; i < 4; i++) {
		int in, out;
		cin >> out >> in;
		current = current - out + in;
		maxnum = max(maxnum, current);
	}
	cout << maxnum << endl;
	return 0;
}