#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define MS(a) memset(a,0,sizeof(a))
#define MP make_pair
#define PB push_back
const int INF = 0x3f3f3f3f;
const ll INFLL = 0x3f3f3f3f3f3f3f3fLL;
inline ll read(){
    ll x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
//////////////////////////////////////////////////////////////////////////
const int maxn = 1e5+10;

int n,m,k[1005],p[1005];
ll dp[1005];
int b[11][maxn],cnt[11];

int main(){
    while(scanf("%d%d",&n,&m)!=EOF){
        int mx = 0, mx2 = 0, mxblood=0;
        for(int i=0; i<11; i++) cnt[i]=0;
        for(int i=0; i<n; i++){
            int a,x;
            scanf("%d%d",&a,&x);
            mx = max(mx,x);
            b[x][cnt[x]++] = a;
            mxblood = max(mxblood,a);
        }
        for(int i=1; i<=m; i++){
            scanf("%d%d",&k[i],&p[i]);
            mx2 = max(mx2,p[i]);
        }
        if(mx >= mx2){
            puts("-1");
            continue;
        }
        // cout << mxblood << endl;
        ll ans = 0;
        for(int d=0; d<11; d++){
            if(cnt[d]==0) continue;
            int blood = mxblood;
            // for(int i=0; i<=m; i++)
                for(int j=0; j<=blood; j++)
                    dp[j] = INFLL;
            for(int i=0; i<=m; i++) dp[0] = 0;
            for(int i=1; i<=m; i++){
                if(p[i]<d) continue;
                for(int j=0; j<=blood; j++){
                    dp[min(blood,j+(p[i]-d))] = min(dp[min(blood,j+(p[i]-d))],min(dp[min(blood,j+(p[i]-d))],dp[j]+k[i]));
                    // cout << i << " " << j << " " << dp[i-1][j] << " " << k[i] << " " << min(blood,j+(p[i]-d)) << " " << dp[i][min(blood,j+(p[i]-d))] << endl;
                }
            }
            for(int i=0; i<cnt[d]; i++){
                int t = b[d][i]; ll tmp=INFLL;
                for(int j=t; j<=blood; j++)
                    tmp = min(tmp,dp[j]);
                // cout << d << " " << t << " " << tmp << endl;
                ans = ans+tmp;
            }
        }
        
        printf("%I64d\n",ans);
    }
}

// 2 2
// 10 5
// 20 10
// 6 7
// 10 11