/*
TASK:school
LANG:C++
*/

# include <iostream.h>


int a[500];
int s;

int Prov()
{int i;
 int j;
 int m;
 s=0;
 for(i=1;i<=a[0];i++){m=a[i];
		      for (j=1;j<=a[0];j++) if ((m==a[j])&&(a[j-1]==a[i+1])) s=s+1;

		     }
 return 0;
}


int main()
{int n;
 int k;
 int i;
 cin>>n>>k;
 Prov();
 for (i=1;i<=2*k;i++) cin>>a[i];
 if (s==1) cout<<n-k+s;
 cout<<n-k;
 cout<<endl;
 return 0;
}