#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;
const int maxn = 1000+10;
typedef long long LL;
LL dp[maxn*2];
vector<int> b[20];
int k[maxn];
int p[maxn];
const LL INF = 0x3f3f3f3f;
int n,m;
LL solve(int x){
    for(int i=0;i<maxn*2;i++){
        dp[i]=INF;
    }
    dp[0]=0;
    for(int i=0;i<maxn*2;i++){
        for(int j=0;j<m;j++){
            if(p[j]<x){
                continue;
            }
            if(i+p[j]-x>=maxn*2){
                continue;
            }
            dp[i+p[j]-x] = min(dp[i+p[j]-x],dp[i]+k[j]);
        }
    }
    for(int i=maxn*2-2;i>=0;i--){
        dp[i] = min(dp[i],dp[i+1]);
    }
    LL ret=0;
    for(int i=0;i<b[x].size();i++){
        int a = b[x][i];
        if(dp[a]==INF){
            return -1;
        }
        ret+=dp[a];
    }
    return ret;
}
int main(){
    while(scanf("%d%d",&n,&m)!=EOF){
        for(int i=0;i<=10;i++){
            b[i].clear();
        }
        int x,y;
        for(int i=0;i<n;i++){
            scanf("%d%d",&x,&y);
            b[y].push_back(x);
        }
        for(int i=0;i<m;i++){
            scanf("%d%d",&k[i],&p[i]);
        }
        LL ans=0;
        for(int i=0;i<=10;i++){
            LL tmp = solve(i);
            if(tmp==-1){
                ans=-1;
                break;
            }
            ans+=solve(i);
        }
        printf("%I64d\n",ans);
    }
    return 0;
}