#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
const int M = 1001;

int n, m;
int a[N], b[N], k[M], p[M];
int f[11][M];

void solve(int de)
{
    for (int i = 1; i <= m; ++i) if (p[i] > de)
    {
        for (int j = 0; j < p[i] - de; ++j)
            f[de][j] = min(f[de][j], k[i]);
        for (int j = p[i] - de; j < M; ++j)
            f[de][j] = min(f[de][j], f[de][j-(p[i]-de)] + k[i]);
    }
}

int main()
{
    while (scanf("%d%d", &n, &m) == 2)
    {
        for (int i = 1; i <= n; ++i)
            scanf("%d%d", a+i, b+i);
        for (int i = 1; i <= m; ++i)
            scanf("%d%d", k+i, p+i);
        memset(f, 0x3f, sizeof f);
        for (int i = 0; i <= 10; ++i) f[i][0] = 0;
        for (int i = 0; i <= 10; ++i)
            solve(i);
        long long ans = 0;
        for (int i = 1; i <= n; ++i)
        {
            if (f[b[i]][a[i]] == 0x3f3f3f3f) { ans = -1; break; }
            ans += f[b[i]][a[i]];
        }
        printf("%I64d\n", ans);
    }
    return 0;
}