rt,全是RE

#include<bits/stdc++.h>
using namespace std;
int t,n;
int ti[100005],va[100005];
int vis[1005][1005];
int ans;
int dfs(int step,int last,int val){
	if(vis[step][last]!=-1) return vis[step][last];
	if(last<0) return -1;
	if(step>n){
		ans=max(ans,val);
		return 0;
	}
	int res1,res2;
	res1=dfs(step+1,last,val);
	res2=dfs(step+1,last-ti[step],val+va[step]);
	vis[step][last]=max(res1,res2);
}
int main(){
	cin>>t>>n;
	memset(vis,-1,sizeof(vis));
	for(int i=1;i<=n;i++){
		cin>>ti[i]>>va[i];
	}
	dfs(1,t,0);
	cout<<ans;
	return 0;
}