1 #include<cstdio>
 2 #include<iostream>
 3 
 4 using namespace std;
 5 
 6 int m,n,v[10004],w[10004],f[10004];
 7 
 8 int main()
 9 {
10     scanf("%d%d",&m,&n);
11     for(int i = 1;i <= n; i++)
12         scanf("%d%d",&w[i],&v[i]);
13     for(int i = 1;i <= n; i++)
14         for(int j = 0;j <= m; j++)
15             if(v[i] <= j)
16                 f[j] = max(f[j],f[j-v[i]] + w[i]);    
17     printf("%d",f[m]);        
18     return 0;
19 }