# include <cstdio>
# include <cstring>
# include <cstdlib>
# include <iostream>
# include <vector>
# include <queue>
# include <stack>
# include <map>
# include <bitset>
# include <set>
# include <cmath>
# include <algorithm>
using namespace std;
# define lowbit(x) ((x)&(-x))
# define pi acos(-1.0)
# define eps 1e-8
# define MOD 1000000007
# define INF 1000000000
# define mem(a,b) memset(a,b,sizeof(a))
# define FOR(i,a,n) for(int i=a; i<=n; ++i)
# define FDR(i,a,n) for(int i=a; i>=n; --i)
# define bug puts("H");
# define lch p<<1,l,mid
# define rch p<<1|1,mid+1,r
# define mp make_pair
# define pb push_back
typedef pair<int,int> PII;
typedef vector<int> VI;
# pragma comment(linker, "/STACK:1024000000,1024000000")
typedef long long LL;
inline int Scan() {
    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 void Out(int a) {
    if(a<0) {putchar('-'); a=-a;}
    if(a>=10) Out(a/10);
    putchar(a%10+'0');
}
const int N=1005;
//Code begin....

LL dp[11][N];
struct Node{int a, b;}node[N*100];

int main ()
{
    int n, m, x, y, z;
    LL ans, top=1LL<<61;
    while (~scanf("%d%d",&n,&m)) {
        ans=0;
        FOR(i,1,n) node[i].a=Scan(), node[i].b=Scan();
        FOR(i,0,10) FOR(j,1,1000) dp[i][j]=top;
        FOR(i,1,m) {
            x=Scan(); y=Scan();
            FOR(j,0,10) {
               z=y-j;
               if (z<=0) continue;
               FOR(k,1,1000) dp[j][k]=min(dp[j][k],dp[j][max(k-z,0)]+x);
            }
        }
        bool flag=false;
        FOR(i,1,n) {
            if (dp[node[i].b][node[i].a]==top) {flag=true; break;}
            ans+=dp[node[i].b][node[i].a];
        }
        if (flag) puts("-1");
        else printf("%lld\n",ans);
    }
    return 0;
}