#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int INF = 0x3f3f3f3f;
const int maxn = 100000+10;
const int maxm = 1000+10;
int A[maxn], B[maxn], P[maxn], K[maxn];
int dp[maxm][11];
int n, m;
void init() {
    memset(dp, INF, sizeof(dp));
    for (int j = 0; j <= 10; j++) {
        dp[0][j] = 0;
        for (int k = 0; k <= m; k++) {
            for (int l = 1; l <= 1000; l++) {
                if (P[k] >= j) {
                    if (l-P[k]+j<0) dp[l][j]=min(dp[l][j], dp[0][j]+K[k]);
                    else dp[l][j]=min(dp[l][j], dp[l-P[k]+j][j] + K[k]); 
                }
            }
        }
    }   
}
int main(int argc, char const *argv[])
{
    while (scanf("%d%d", &n, &m) != EOF) {
        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]);
        init();
        LL ans = 0;
        for (int i = 0; i < n; i++) {
            if (dp[A[i]][B[i]] == INF) {ans = -1; break;}
            ans += dp[A[i]][B[i]];
        }
        printf("%lld\n", ans);
    }
    return 0;
}