public static void main(String[] args) {

Scanner sc=new Scanner(System.in);

int n=sc.nextInt();

int m=sc.nextInt();

int a[]=new int[n];

int b[]=new int[n];

int c[]=new int[m];

int d[]=new int[m];

for(int i=0;i<n;i++){

a[i]=sc.nextInt();

b[i]=sc.nextInt();

}

int sum=0,count;

for(int i=0;i<m;i++){

c[i]=sc.nextInt();

d[i]=sc.nextInt();

count=0;

for(int j=0;j<n;j++){

if((c[i]>=a[j]&&c[i]<=b[j])||(d[i]>=a[j]&&d[i]<=b[j])||(c[i]<=a[j]&&d[i]>=b[j]))

count++;

}

sum+=count;

}

System.out.println(sum);

}

}