#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 1e5 + 5;
const int M = 1e3 + 5;
int a[N], b[N], k[M], p[M];
ll f[M][15];
int main() {
    int n, m;
    while(~scanf("%d%d", &n, &m)) {
        for(int i = 0; i < n; i++) {
            scanf("%d%d", &a[i], &b[i]);
        }
        for(int i = 0; i < m; i++) {
            scanf("%d%d", &k[i], &p[i]);
        }
        for(int i = 0; i <= 1000; i++) {
            for(int j = 0; j <= 10; j++) {
                f[i][j] = 1e18;
            }
        }
        for(int i = 0; i <= 10; i++) {
            f[0][i] = 0;
        }
        for(int i = 0; i <= 10; i++) {
            for(int j = 0; j < m; j++) {
                int det = p[j] - i;
                if(det <= 0) continue;
                for(int l = 0; l <= 1000; l++) {
                    f[l][i] = min(f[l][i], f[max(0, l - det)][i] + k[j]);
                }
            }
        }
        ll ans = 0;
        for(int i = 0; i < n; i++) {
            if(f[a[i]][b[i]] == 1e18) ans = -1;
            if(~ans) ans += f[a[i]][b[i]];
        }
        printf("%lld\n", ans);
    } 
    return 0;
}