#include<bits/stdc++.h>
using namespace std;
typedef long long LL;

inline LL read(){
    char ch = getchar(); LL x = 0, op = 1;
    while (ch < '0' || '9' < ch) { if (ch == '-') op = -1; ch = getchar(); }
    while ('0' <= ch && ch <= '9') { x = x*10 + ch-'0'; ch = getchar(); } 
    return op * x;
}

LL f[2005][12], w[1005], cost[1005];
LL n, m, a[100005], b[100005], A, B, best;
LL ans;

int main() {
    while (~scanf("%I64d%I64d", &n, &m)) {
        A = B = ans = best = 0;
        memset(f, 0x3f, sizeof f);
        for (LL i=1; i<=n; i++) {
            a[i] = read(); b[i] = read(); 
            A = max(A, a[i]); B = max(B, b[i]);
        }
        for (LL i=1; i<=m; i++) {
            cost[i] = read(); w[i] = read(); 
            best = max(best, w[i]);
        }
        if (best <= B) {
            puts("-1"); continue;
        }
        
        for (LL t=0; t<=B; t++) {
            f[0][t] = 0;
            for (LL i=0; i<=A+1000; i++) {
                if (f[i][t] >= 1e18) continue;
                for (LL j=1; j<=m; j++)
                    if (w[j] > t && i+w[j]-t <= A+1000) 
                        f[i+w[j]-t][t] = min(f[i+w[j]-t][t], f[i][t] + cost[j]);
            }
            for (LL i=A+1000; i>=0; i--)
                f[i][t] = min(f[i][t], f[i+1][t]);
        }
        
        for (LL i=1; i<=n; i++) {
            if (f[a[i]][b[i]] >= 1e18) {
                ans = -1; break;
            }
            ans += f[a[i]][b[i]];
        }
        printf("%I64d\n", ans);
    }
    return 0;
}