#include<bits/stdc++.h>
#define ll long long
#define uint unsigned int
#define ull unsigned long long
#define inf 1010000000
#define infll 1010000000000000000ll
#define vi vector<int>
#define vll vector<ll>
#define pb push_back
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pdd pair<double,double>
#define mpr make_pair
#define fi first
#define se second
#define pq priority_queue<int>
#define pqll priority_queue<ll>
#define up(x,y) (x<(y)?x=(y):0)
#define dn(x,y) (x>(y)?x=(y):0)
#define ad(x,y) (x=(x+(y))%mod)
#define cbn(x,y) ((ll)fac[x]*inv[y]%mod*inv[(x)-(y)]%mod)
#define N 100009
using namespace std;

int read(); ll readll();

int n, m, a[N], b[N], cost[N], damage[N], dp[1009], ans[N];
int main(){
    while (~scanf("%d %d", &n, &m)){
        int i;
        for (i = 1; i <= n; i++) scanf("%d %d", &a[i], &b[i]);
        for (i = 1; i <= m; i++) scanf("%d %d", &cost[i], &damage[i]);
        for (i = 0; i <= 10; i++){
            memset(dp, 60, sizeof(dp));
            dp[0] = 0;
            for (int j = 1; j <= 1000; j++)
                for (int k = 1; k <= m; k++)
                    dn(dp[j], dp[j - max(0, damage[k] - i)] + cost[k]);
            for (int j = 1; j <= n; j++) if (b[j] == i) ans[j] = dp[a[j]];
        }
        for (i = 1; i <= n; i++) if (ans[i] > inf) break;
        if (i <= n) puts("-1"); else{
            ll sum = 0;
            for (i = 1; i <= n; i++) sum += ans[i];
            printf("%lld\n", sum);
        }
    }
    return 0;
}

int read(){
    int x=0; char ch=getchar(); bool flag=0;
    while (ch<'0' || ch>'9'){ if (ch=='-') flag=1; ch=getchar(); }
    while (ch>='0' && ch<='9'){ x=x*10+ch-'0'; ch=getchar(); }
    return flag?-x:x;
}
ll readll(){
    ll x=0; char ch=getchar(); bool flag=0;
    while (ch<'0' || ch>'9'){ if (ch=='-') flag=1; ch=getchar(); }
    while (ch>='0' && ch<='9'){ x=x*10+ch-'0'; ch=getchar(); }
    return flag?-x:x;
}