#include <bits/stdc++.h>
#define ll long long 
using namespace std;
const int maxn=100010,maxm=1010;
ll a[maxn],b[maxn],k[maxm],p[maxm],dp[maxm][11];

long double aw(long double x1,long double y1,long double x2,long double y2) {
    return sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
}

long double cv(long double a,long double b,long double c) {
    return acos((b*b+c*c-a*a)/(2*b*c));
}

int oneNumInBinary(ll n) { 
    ll cnt=0;
    while(n)  n=n&(n-1),cnt++;
    return cnt;
}

ll qpow(ll a,ll b) {
    ll ans=1;    
    while(b) {       
        if(b&1) ans=(ans*a)%999;        
        a=a*a%999;      
        b>>=1;    
    }   
    return ans;
}

inline int read() {
    int 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;
}

inline string readstring() {
    string str;
    char s=getchar();
    while(s==' '||s=='\n'||s=='\r') {s=getchar();}
    while(s!=' '&&s!='\n'&&s!='\r') {str+=s; s=getchar();}
    return str;
}

int main()
{
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        ll up1=0,up2=0,hp=0;
        for(int i=0; i<n; i++)  {
            scanf("%lld %lld",&a[i],&b[i]);
            up1=max(up1,b[i]);//防御力最大值 
            hp=max(hp,a[i]);//生命值最大值 
        }
        for(int i=0; i<m; i++) {
            scanf("%lld %lld",&k[i],&p[i]);
            up2=max(up2,p[i]);//伤害最大值 
        }
        if(up1>=up2)  {
            printf("-1\n");
            continue;
        }
        memset(dp,0,sizeof(dp));
        for(int i=0; i<=10; i++)//0<=b[i]<=10
        {
            for(int j=1; j<=hp; j++)//造成伤害值,0<=p[i]<=1000
            {
                dp[j][i]=1e18;
                for(int u=0; u<m; u++)//第u个技能
                {
                    ll dmg=p[u]-i;//第u个技能能造成的伤害
                    if(dmg<=0)  continue;
                    if(dmg>=j)  dp[j][i]=min(dp[j][i],k[u]);
                    else  dp[j][i]=min(dp[j][i],dp[j-dmg][i]+k[u]);
                }
            }
        }
        ll ans=0;
        for(int i=0; i<n; i++)
            ans += dp[a[i]][b[i]];
        printf("%lld\n",ans);
    }
    return 0;
}