#include<bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define CLR(A, X) memset(A, X, sizeof(A))
using namespace std;

typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
const double eps = 1e-10;
int dcmp(double x){if(fabs(x)<eps) return 0; return x<0?-1:1;}
const int INF = 0x3f3f3f3f;
const LL MOD = 21092013;
const int N = 1e5+5;

PII mon[N];
PLL ski[1005];
LL dp[1005][15];

int main() {
    int n, m;
    while(~scanf("%d%d", &n, &m)) {
        CLR(dp, -1);
        for(int i = 0; i < n; i++) scanf("%d%d", &mon[i].fi, &mon[i].se);
        for(int i = 0; i < m; i++) scanf("%lld%lld", &ski[i].fi, &ski[i].se);
        for(int d = 0; d <= 10; d++) {
            dp[0][d] = 0;
            for(int i = 0; i < m; i++) if(ski[i].se > d) {
                int x = ski[i].se-d;
                for(int h = 0; h < x; h++) {
                    if(dp[h][d] == -1) dp[h][d] = ski[i].fi;
                    else dp[h][d] = min(dp[h][d], ski[i].fi);
                }
                for(int h = x; h <= 1000; h++) if(dp[h-x][d] != -1) {
                    if(dp[h][d] == -1) dp[h][d] = dp[h-x][d]+ski[i].fi;
                    else dp[h][d] = min(dp[h][d], dp[h-x][d]+ski[i].fi);
                }
            }
        }
        for(int d = 0; d <= 10; d++) {
            for(int h = 1000; h >= 1; h--) {
                if(dp[h-1][d] == -1) dp[h-1][d] = dp[h][d];
                else dp[h-1][d] = min(dp[h-1][d], dp[h][d]);
            }
        }
        bool flag = 1;
        LL ans = 0;
        for(int i = 0; i < n; i++) {
            if(dp[mon[i].fi][mon[i].se] == -1) {
                flag = 0;
                break;
            }
            ans += dp[mon[i].fi][mon[i].se];
//            printf("? = %d %d %lld\n", mon[i].fi, mon[i].se, dp[mon[i].fi][mon[i].se]);
        }
        if(!flag) ans = -1;
        printf("%lld\n", ans);
    }
    return 0;
}