#include <iostream>

int minBlood = 0, blood = 0;

int main() {
    int n, current;
    std::cin >> n;
    for (int i = 0; i < n; i++) {
        std::cin >> current;
        blood += current;
        minBlood = std::min(minBlood, blood);
    }
    if (minBlood >= 0) {
        std::cout << 1 << std::endl;
    } else {
        std::cout << -minBlood + 1 << std::endl;
    }

    return 0;
}