#include<iostream>

#include<cstdio>

#include<algorithm>

#include<cstring>

typedef long long ll;

using std::max;

const int N=+;

ll n,tot=;

ll dp[N][N],w[N],c[N];

inline ll read()

{

    char ch=getchar();

    ll s=,f=;

    while (ch<''||ch>'') {if (ch=='-') f=-;ch=getchar();}

    while (ch>=''&&ch<='') {s=(s<<)+(s<<)+ch-'';ch=getchar();}

    return s*f;

}

void dfs(int now)

{

    ll t=read(),x=read();

    t<<=;

    if (x)

    {

        for (ll i=;i<=x;i++) w[i]=read(),c[i]=read();

        for (ll i=;i<=x;i++)

        {

            for (ll j=n;j>=c[i];j--) if (j-c[i]>=t) dp[now][j]=max(dp[now][j],dp[now][j-c[i]]+w[i]);

        }

        return;

    }

    ll l=++tot;dfs(tot);

    ll r=++tot;dfs(tot);

    for (ll i=t;i<=n;i++)

        for (ll j=;j<=i-t;j++)

        {

            dp[now][i]=max(dp[now][i],dp[l][j]+dp[r][i-t-j]);

        }

}

int main()

{

    n=read();n--;

    dfs();

    printf("%lld\n",dp[][n]);

    return ;

}