#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N = 100005, M = 1005;
const LL inf = 1e18;
LL dp[11][M];
LL a[N], b[N], k[M], p[M];
int main() {
    int n, m;
    while (~scanf("%d%d", &n, &m)) {
        memset(dp, 0, sizeof(dp));
        for (int i = 1; i <= n; ++i)    scanf("%I64d%I64d", &a[i], &b[i]);
        for (int i = 1; i <= m; ++i)    scanf("%I64d%I64d", &k[i], &p[i]);
        for (int i = 0; i <= 10; ++i)
            for (int j = 1; j <= 1000; ++j) {
                dp[i][j] = inf;
                for (int l = 1; l <= m; ++l) {
                    LL t = p[l] - i;
                    if (t <= 0)    continue;
                    if (t >= j)    dp[i][j] = min(dp[i][j], k[l]);
                    else    dp[i][j] = min(dp[i][j], dp[i][j - t] + k[l]);
                }
            }
        LL ans = 0;
        for (int i = 1; i <= n; ++i)    ans += dp[b[i]][a[i]];
        if (ans > inf)    puts("-1");
        else cout << ans << endl;
    }
    return 0;
}