#include <stdio.h>

int main (){
   int n;scanf("%d",&n);
   int A[200001];for(int i = 0;i < n*2;i++)scanf("%d",&A[i]);
   int h=0,t=0;
   if(n == 1){printf("%d",A[0] - A[1]);return 0;}
   for(int i = 0;i < n;i++){
      if(i%2 == 0)h += A[i];
      else t += A[i];
   }
   for(int i = n;i < n*2;i++){
      if(i%2 == 0)t += A[i];
      else h += A[i];
   }
   printf("%d\n",h-t);
   printf("h:%d t:%d",h,t);
}