#include <bits/stdc++.h>
#define REP(i, a, b) for (int i = a; i <= b; ++i)
#define PER(i, a, b) for (int i = a; i >= b; --i)
#define RVC(i, S) for (int i = 0; i < S.size(); ++i)
#define mp make_pair
#define pb push_back
#define debug(...) fprintf(stderr, __VA_ARGS__)
#define fi first
#define se second
using namespace std;
 
typedef long long LL;
typedef pair<int, int> pii;
typedef vector<int> VI;

const int N = 100005;
int n, m, ai[N], bi[N], ki[N], pi[N], dp[11][2005];

int main(){
    while (scanf("%d%d", &n, &m) == 2){
        REP(i, 1, n) scanf("%d%d", &ai[i], &bi[i]);
        REP(i, 1, m) scanf("%d%d", &ki[i], &pi[i]);
        REP(t, 0, 10){
            memset(dp[t], 0x3f, sizeof dp[t]);
            dp[t][0] = 0;
            REP(i, 1, 2000) REP(j, 1, m)
                if (pi[j] > 0 && i >= pi[j])
                    dp[t][i] = min(dp[t][i], dp[t][i - pi[j]] + ki[j]);
            PER(i, 1999, 1) dp[t][i] = min(dp[t][i], dp[t][i + 1]);
            REP(j, 1, m) --pi[j];
        }
        LL ans = 0;
        REP(i, 1, n){
            if (dp[bi[i]][ai[i]] == 0x3f3f3f3f){
                ans = -1; break;
            }
            else ans += dp[bi[i]][ai[i]];
        }
        printf("%I64d\n", ans);
    }
    return 0;
}