#include<bits/stdc++.h>
using namespace std;

int main()
{
    int l, n, w, sum = 0;
    cin >> l >> n;
    for(int i = 0; i < n; i++)
    {
        cin >> w;
        sum += w;
    }

    int ans = 0, p = l;
    while(sum > 0)
    {
        l--;
        sum--;
        if(l == 0)
        {
            l = p;
            ans++;
        }
    }

    if(l != p && l > 0) ans++;

    cout << ans << endl;
}