#include <bits/stdc++.h>

template <class T>
void scan(T &x) {
    register char ch; x = 0;
    for (ch = getchar(); ~ch && (ch < '0' || ch > '9'); ch = getchar());
    for (; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - '0';
}

typedef long long ll;
const int MAXP = 2000;

int n, m;
int k[1005], p[1005];

struct Monster {
    int a, b;
    
    bool operator < (const Monster &rhs) const {
        return b < rhs.b;
    }
    
    void scan() {
        ::scan(a); ::scan(b);
    }
} mons[100005];

int dp[2005];

int main() {
    while (~scanf("%d%d", &n, &m)) {
        for (int i = 1; i <= n; ++i) mons[i].scan();
        for (int i = 1; i <= m; ++i) {
            scan(k[i]); scan(p[i]);
        }
        
        std::sort(mons + 1, mons + n + 1);
        
        int mx = 0;
        for (int i = 1; i <= m; ++i) mx = std::max(mx, p[i]);
        if (mx <= mons[n].b) {
            puts("-1"); continue;
        }
        
        ll ans = 0;
        
        for (int l = 1, r = 1, b = 0; b <= 10; ++b, l = r) {
            while (r <= n && mons[r].b == b) ++r;
            
            memset(dp, 0x7f, sizeof dp);
            dp[0] = 0;
            
            for (int i = 1; i <= m; ++i) {
                if ((p[i] - b) <= 0) continue;
                for (int j = (p[i] - b); j <= MAXP; ++j)
                    dp[j] = std::min(dp[j], dp[j - (p[i] - b)] + k[i]);
            }
            
            for (int i = MAXP - 1; i; --i)
                dp[i] = std::min(dp[i], dp[i + 1]);
            
            for (int i = l; i < r; ++i)
                ans += dp[mons[i].a];
        }
        
        std::cout << ans << std::endl;
    }
    
    return 0;
}