int main()
{
	int l,m; 
	scanf("%d%d",&l,&m);
	int arr[m*2];
	for(int i=0;i<6;i++){
	scanf("%d",arr[i]);	
	}
	
	int min=arr[0];
	int max=arr[0];
	for(int i=0;i<m*2;i++){
		if(max<arr[i])max=arr[i];
		if(min>arr[i])min=arr[i];
	}
	printf("%d",l+1-max+min);
	return 0;
}```