#include <vector>
#include <queue>
#include <list>
#include <iostream>
#include <array>
#include <string>
#include <numeric>
#include <algorithm>
#include <cmath>

using namespace std;

using ll = long long;
using ld = long double;

int main()
{
    ll w, res = 0;
    cin >> w;
    auto dfs = [&w, &res](auto self) -> ll
    {
        ll m;
        int n;
        cin >> m >> n;
        vector<ll> children;
        for (int i = 0; i < n; ++i)
            children.push_back(self(self));
        sort(children.rbegin(), children.rend());
        ll sum = accumulate(children.begin(), children.end(), 0ll);
        while (sum > w)
        {
            sum -= children.back();
            children.pop_back();
            ++res;
        }
        if (sum + m < w)
            return sum + m;
        m -= w - sum;
        res += m / w + 1;
        return m % w;
    };
    ll last = dfs(dfs);
    cout << res + (last + w - 1) / w << '\n';
    return 0;
}