#include <bits/stdc++.h>
using  namespace  std;

#define ff first
#define ss second
#define pb push_back
#define ll long long
#define ull unsigned long long
#define min3(a, b, c) min(a, min(b, c))
#define max3(a, b, c) max(a, max(b, c))
#define mst(ss,b) memset(ss,b,sizeof(ss));
#ifdef Cyberdebut
#define dbg(x) cerr << #x << " = " << x << endl
#else
#define dbg(x)
#endif
typedef pair <int, int> pii;
ll gcd(ll a, ll b){return a ? gcd(b%a,a):b;}
ll pow_mod(ll x, ll n, ll mod){ll ret=1LL;while(n){if(n&1)ret=ret*x%mod;x=x*x%mod;n>>=1;}return ret;}
const int inf = 0x3f3f3f3f;
const ll INF = (1LL<<62)-1;
const ll mod = 1e9+7;
const int N = 1e5+5;

ll dp[1005][15];
int n, m, a[N], b[N], k[N], p[N];

int  main(){
    while(~scanf("%d%d", &n, &m)){
        for(int i=1; i<1005; i++)for(int j=0; j<15; j++)dp[i][j] = INF;
        for(int j=0; j<15; j++)dp[0][j] = 0;
        int mxa = 0, mxb = 0;
        for(int i=1; i<=n; i++)scanf("%d%d", &a[i], &b[i]), mxa = max(mxa, a[i]), mxb = max(mxb, b[i]);
        for(int i=1; i<=m; i++)scanf("%d%d", &k[i], &p[i]);
        for(int i=1; i<=mxa; i++){
            for(int j=0; j<=mxb; j++){
                for(int ki=1; ki<=m; ki++){
                    if(p[ki] <= j)continue;
                    int del = p[ki]-j;
                    dp[i][j] = min(dp[i][j], dp[max(0, i-del)][j]+k[ki]);
                }
            }
        }
        ll ans = 0; int fg = 1;
        for(int i=1; i<=n; i++){
            if(dp[a[i]][b[i]] >= INF){
                fg = 0; break;
            }
        }
        if(!fg)puts("-1");
        else{
            for(int i=1; i<=n; i++)ans += dp[a[i]][b[i]];
            printf("%lld\n", ans);
        }
    }
    return 0;
}


//    lower_bound()
//    __builtin_popcount()
//    ios::sync_with_stdio(false);
//    freopen("in.txt","r",stdin);
//    freopen("out.txt","w",stdout);
//    const double eps=1e-12;
//    #pragma comment(linker,"/STACK:102400000,102400000")