#include<bits/stdc++.h>
using namespace std;

const int N = 100001, M = 1001;

int n, m;
int f[11][M], a[N], b[N], cost[M], p[M];

int main(){
    int i, j, k;
    while(scanf("%d",&n)!=EOF){
        scanf("%d",&m);
        memset(f, 0x3f, sizeof f);
        for(i=0;i<n;i++)scanf("%d%d",a+i, b+i);
        for(i=0;i<m;i++)scanf("%d%d",cost+i, p+i);
        for(k = 0; k < 11; k++){
            f[k][0] = 0;
            for(i = 1; i < M; i++){
                for(j = 0; j < m; j++){
                    f[k][i] = min(f[k][i], f[k][max(i - max(0, p[j]-k), 0)] + cost[j]);
                }
            }
        }
        long long ans = 0;
        for(i=0;i<n;i++){
            if(f[b[i]][a[i]] == 0x3f3f3f3f){
                ans = -1;
                break;
            }
            ans += f[b[i]][a[i]];
        }
        printf("%lld\n",ans);
    }
}