# include <iostream>
# include <algorithm>
using namespace std;

int w[30], p[30], f[30];

int main()
{
	int n, m;
	cin >> m >> n;
	for (int i = 1; i <= n; i++)
	{
		int x, y;
		cin >> x >> y;
		w[i] = x;
		p[i] = x * y;
	}
	for (int i = 1; i <= n; i++)
		for (int j = m; j >= w[i]; j--)
			f[j] = max(f[j - 1], f[j - w[i]] + p[i]);
	cout << f[m] << endl;
	return 0;
}

有两个点WA了，请大佬帮忙看看