#include<bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
#define rep(i,a,b) for (int i=a; i<=b; ++i)
#define per(i,b,a) for (int i=b; i>=a; --i)
#define mes(a,b)  memset(a,b,sizeof(a))
#define INF 1e18
#define MP make_pair
#define PB push_back
#define fi  first
#define se  second
typedef long long ll;
const int N = 100005, M = 1005;

int n, m, a[N], b[N], k[M], p[M];
ll  dp[M][12];
int main()
{
    while(~scanf("%d%d", &n, &m))
    {
        rep(i,1,n) scanf("%d%d", &a[i], &b[i]);
        rep(i,1,m) scanf("%d%d", &k[i], &p[i]);
        rep(bi,0,10) rep(i,0,M-1) {
            if(i==0) dp[i][bi] = 0;
            else dp[i][bi] = INF;
        }
        rep(bi,0,10) rep(ai,1,M-1) rep(i,1,m)
            if(p[i]>bi)
        {
            if(ai-(p[i]-bi)>=0)
                dp[ai][bi] = min(dp[ai-(p[i]-bi)][bi]+k[i], dp[ai][bi]);
            else
                dp[ai][bi] = min(1LL*k[i], dp[ai][bi]);
        }
        ll  ans = 0;
        bool flag=0;
        rep(i,1,n) {
            if(dp[a[i]][b[i]]==INF) flag=1;
            else ans += dp[a[i]][b[i]];
        }
        if(flag) puts("-1");
        else printf("%I64d\n", ans);
    }

    return 0;
}