import math
sanple=int(input())
score=[]
for i in range(sanple):
 score.append(list(map(int,str(input()).split(" "))))
sumscore=[0,0]
for i in range(sanple):
 minscore=999**999
 sumscore[0]+=score[i][0]
 minscore=abs(sumscore[1]-sumscore[0])
 sumscore[0]-=score[i][0]
 sumscore[1]+=score[i][1]
 if abs(sumscore[1]-sumscore[0])<minscore:
  minscore=abs(sumscore[1]-sumscore[0])
 else:
  sumscore[0]+=score[i][0]
  sumscore[1]-=score[i][1]
print(minscore)