#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
const int maxn = 100009;
int n , m;
int a[maxn] , b[maxn];
int k[1009] , p[1009];
long long f[11][2009];
int max_hurt , max_def;

void init()
{
    bool flag[11];
    memset(flag,false,sizeof(flag));
    max_hurt = max_def = -1;
    for( int i = 1; i <= n; i++ ) scanf("%d%d",&a[i],&b[i]) , flag[ b[i] ] = true , max_def = max( max_def , b[i] );
    for( int i = 1; i <= m; i++ ) scanf("%d%d",&k[i],&p[i]) , max_hurt = max( max_hurt , p[i] );
    if ( max_def >= max_hurt ) return;
    memset(f,0x3f,sizeof(f));
    for( int i = 0; i <= 10; i++ )
    if ( flag[i] )
    {
        f[i][0] = 0;
        for( int j = 1; j <= m; j++ )
        if ( p[j] > i )
        {
            for( int life = p[j]-i; life <= 2000; life++ ) f[i][life] = min( f[i][life] , min( f[i][life+1] , f[i][life-p[j]+i] + k[j] ) );
        }
        for( int life = 2000; life >= 0; life-- ) f[i][life] = min( f[i][life] , f[i][life+1] );
    }
}

int main()
{
    while( scanf("%d%d",&n,&m) == 2 )
    {
        init();
        if ( max_def >= max_hurt )
        {
            puts("-1");
            continue;
        }
        long long ans = 0;
        for( int i = 1; i <= n; i++ ) ans += f[b[i]][a[i]];
        printf("%I64d\n",ans);
    }

    return 0;
}