#include <iostream>  
#include <stdlib.h>  
#include <stdio.h>  
#include <string.h>  
#include <stack>  
#include <queue>  
#include <map>  
#include <set>  
#include <vector>  
#include <math.h>  
#include <bitset>  
#include <algorithm>  
#include <climits>  
using namespace std;  
long long  a[100005],b[100005];  
long long  k[1005],p[1005];  
long long dp[1005][15];  
int main (){  
    long long n,m;  
    while (scanf ("%lld%lld",&n,&m)!=EOF){  
        long long  maxb=0,maxa=0;  
        for (int i=0;i<n;i++){  
            scanf ("%lld%lld",&a[i],&b[i]);  
            maxa=max(maxa,a[i]);  
            maxb=max(maxb,b[i]);  
        }  
        long long maxp=0;  
        for (int i=0;i<m;i++){  
            scanf ("%lld%lld",&k[i],&p[i]);   
            maxp=max(maxp,p[i]);  
        }  
        if (maxb>=maxp){  
            printf ("-1\n");  
            continue;  
        }  
        memset(dp,0x3f3f3f3f,sizeof(dp));  
        for (int i=0;i<=10;i++)  
            dp[0][i]=0;  
        for (int i=0;i<=10;i++){//    护甲   
            for (int j=1;j<=maxa;j++){//   血量   
                for (int l=0;l<m;l++){//      技能数   
                    if(p[l]-i>=j){  
                        dp[j][i]=min(dp[j][i],k[l]);  
                    }  
                    else if (p[l]-i>0){  
                        dp[j][i]=min(dp[j][i],dp[j-(p[l]-i)][i]+k[l]);  
                    }  
                }  
            }  
        }  
        long long ans=0;  
        for (int i=0;i<n;i++){  
            ans+=dp[a[i]][b[i]];   
        }  
        printf ("%lld\n",ans);  
    }  
    return 0;  
}