#include<bits/stdc++.h> using namespace std; int n,m,ans=0; int a[36],b[36]; void work(int dep,int time,int value){ if(time>n)return; if(dep>m){ ans=max(ans,value); return; } work(dep+1,time+a[dep],value+b[dep]); work(dep+1,time,value); } int main(){ cin>>n>>m; for(int i=1;i<=m;i++){ cin>>a[i]>>b[i]; } work(1,0,0); cout<<ans<<endl; return 0; }