#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long LL;
#define N 100000 + 5
#define M 1000 + 5
#define INF 1234567890

int n, m, Hp[N], Def[N], Mp[M], Atk[M], Dp[11][M], Min[11][M];
LL ans;

int main()
{
    while (scanf("%d%d", &n, &m) == 2)
    {
        for (int i = 1; i <= n; i ++)
            scanf("%d%d", Hp + i, Def + i);
        for (int i = 1; i <= m; i ++)
            scanf("%d%d", Mp + i, Atk + i);
        for (int i = 0; i <= 10; i ++)
        {
            Dp[i][0] = 0;
            for (int j = 1; j < M; j ++)
                Dp[i][j] = INF;
            for (int t = 1; t <= m; t ++)
            {
                int w = Mp[t], v = Atk[t] - i;
                if (v <= 0) continue ;
                for (int j = 0; j < M; j ++)
                    Dp[i][min(j + v, M - 1)] = min(Dp[i][min(j + v, M - 1)], Dp[i][j] + w);
            }
            for (int j = M - 1; j; j --)
                Min[i][j] = min(Dp[i][j], j == M - 1 ? INF : Min[i][j + 1]);
        }
        ans = 0;
        for (int i = 1; ~ans && i <= n; i ++)
        {
            ans += Min[Def[i]][Hp[i]];
            if (Min[Def[i]][Hp[i]] == INF) ans = -1;
        }
        printf("%I64d\n", ans);
    }
    return 0;
}