#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#ifdef APURBA
#include "DEBUG_TEMPLATE.h"
#else
#define HERE
#define debug(args...)
#endif
#define ALL(x) x.begin(),x.end()

int ans;
int w;

int solve()
{
    int m,n;
    cin>>m>>n;
    vector<int> x;
    for(int i=0;i<n;i++)
    {
        x.push_back(solve());
    }
    sort(ALL(x));
    int now=0 , pos = 0;
    while(pos<n and now+x[pos] <= w)
    {
        now+=x[pos];
        pos++;
    }
    ans+=n-pos;
    now+=m;
    ans+=now/w;
    now%=w;
    return now;
}


void TEST_CASES()
{
    cin>>w;
    int x=solve();
    ans+=x>0;
    cout<<ans;
}


/*
*/

int32_t main()
{
#ifndef APURBA
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
#endif
    //freopen("input.txt","r",stdin);
    //freopen("out1.txt","w",stdout);
    int t=1;
    //cin>>t;
    while(t--)
    {
        TEST_CASES();
    }
    return 0;
}