#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "cstring"
using namespace std;
int n,c;
vector> v;
int memo[105][10005];
int dp(int i,int coins_left){
    if(i == -1){
        return 0;
    }
    if(memo[i][coins_left] != -1){
        return memo[i][coins_left];
    }
    int res = -500;
    res = max(res,dp(i-1,coins_left));
    if(coins_left - v[i].second >= 0){
        res = max(res,dp(i-1,(coins_left -v[i].second)+ v[i].first)+1);
    }
    return  memo[i][coins_left] =res;
}
int main() {
    ios_base::sync_with_stdio(false);

    cin >> n >> c;
        for (int i = 0; i < c; i++) {
        int a,b;
        cin >> a >> b;
        v.push_back(make_pair(b,a));
    }
    sort(v.begin(),v.end());
    for (int i = 0; i < 105; i++) {
        for (int j = 0; j < 10005; j++) {
            memo[i][j] = -1;
        }
    }
    cout << dp(c-1,n);
}