#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
#include <iostream>
#include <string>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <bitset>
#include <stack>
using namespace std;

#define REP(i,n) for ( int i=1; i<=int(n); i++ )  
#define MP make_pair
#define PB push_back
#define SZ(x) (int((x).size()))
#define ALL(x) (x).begin(), (x).end()
#define X first
#define Y second
template<typename T> inline bool chkmin(T &a, const T &b) { return a > b ? a = b, 1 : 0; }
template<typename T> inline bool chkmax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }

typedef long long LL;
typedef long double LD;
typedef unsigned int uint;
typedef pair<int, int> pii;
const int INF = 0x3f3f3f3f;

LL dp[1005][15];
pii a[100005];
pii val[1005];
int main() {
    int n, m;
    while(~ scanf("%d %d", &n, &m) ) {
        for(int i = 1; i <= n; i ++) 
            scanf("%d %d", &a[i].X, &a[i].Y);
        for(int i = 1; i <= m; i ++) 
            scanf("%d %d", &val[i].X, &val[i].Y);
        memset(dp, 0x3f, sizeof(dp));
        memset(dp[0], 0, sizeof(dp[0]));
        for(int k = 1; k <= m; k ++)
            for(int i = 1; i <= 1001; i ++)
                for(int j = 0; j <= 11; j ++) {
                    if(val[k].Y > j) 
                        dp[i][j] = min(dp[i][j], dp[max(0, i - (val[k].Y - j))][j] + val[k].X);
                }
        LL ans = 0;
        for(int i = 1; i <= n; i ++) {
            ans += dp[a[i].X][a[i].Y];
            ans = min(ans, (1LL << 60));
        }
        if(ans >= (1LL << 60)) puts("-1");
        else printf("%I64d\n", ans);
    }
}