[cpp]
#include <cstdio>
const int maxm = 30000 + 10;
const int maxn =30;
int v[maxn], p[maxn];
int dp[maxm] = {0};
int main()
{
int n, m;
int i, j;
scanf("%d%d", &n, &m);
for (i = 0; i < m; i++)
scanf("%d%d", &v[i], &p[i]);
for (i = 0; i < m; i++)
for (j = n; j >= v[i]; j--)
if (dp[j - v[i]] + v[i] * p[i] > dp[j])
dp[j] = dp[j - v[i]] + v[i] * p[i];
printf("%d\n", dp[n]);
return 0;
}
#include <cstdio>
const int maxm = 30000 + 10;
const int maxn =30;
int v[maxn], p[maxn];
int dp[maxm] = {0};
int main()
{
int n, m;
int i, j;
scanf("%d%d", &n, &m);
for (i = 0; i < m; i++)
scanf("%d%d", &v[i], &p[i]);
for (i = 0; i < m; i++)
for (j = n; j >= v[i]; j--)
if (dp[j - v[i]] + v[i] * p[i] > dp[j])
dp[j] = dp[j - v[i]] + v[i] * p[i];
printf("%d\n", dp[n]);
return 0;
}