#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define mkp make_pair
#define fi first
#define se second
#define ll long long
#define M 1000000007
#define all(a) a.begin(), a.end()

const int inf = 1e9;
const int maxn = 100100, maxm = 1010;
int a[maxn], b[maxn];
int k[maxm], p[maxm];
int f[12][maxm * 2];
int n, m;

int main(){
    while(~scanf("%d%d", &n, &m)){
        for(int i = 1; i <= n; ++i) scanf("%d%d", a + i, b + i);
        for(int i = 1; i <= m; ++i) scanf("%d%d", k + i, p + i);
        for(int i = 0; i <= 10; ++i){
            memset(f[i], 127, sizeof(f[i]));
            f[i][0] = 0;
            for(int j = 1; j <= m; ++j)
                if(p[j] > i)
                    for(int l = p[j] - i; l <= 2000; ++l)
                        f[i][l] = min(f[i][l], f[i][l - (p[j] - i)] + k[j]);
            for(int l = 1999; l >= 0; --l)
                f[i][l] = min(f[i][l], f[i][l + 1]);
        }
        bool flag = 1;
        ll ans = 0;
        for(int i = 1; i <= n; ++i){
            if(f[b[i]][a[i]] > inf) flag = 0;
            else ans += f[b[i]][a[i]];
        }
        if(flag) printf("%I64d\n", ans);
        else printf("-1\n");
    }
    
    return 0;
}