#include <iostream>
#include <map>
#include <vector>

using namespace std;

int count_segments(const vector<int> &a, const int s)
{
    const int n = a.size();

    map<int, int> num_prefix;
    num_prefix[0] = 1;

    int count = 0, prefix_sum = 0;
    for (int i = 0; i < n; i++) {
        prefix_sum += a[i];
        count += num_prefix[prefix_sum - s];
        num_prefix[prefix_sum]++;
    }

    return count;
}

int main(void)
{
    int s, n;
    cin >> s >> n;

    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }

    cout << count_segments(a, s) << endl;
    
    return 0;
}