from collections import defaultdict,deque
import sys,heapq,bisect,math,itertools,string,queue,copy,time
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
eps = 10**-7
def inp(): return int(sys.stdin.readline())
def inpl(): return list(map(int, sys.stdin.readline().split()))
def inpl_str(): return list(sys.stdin.readline().split())

N = inp()
sA = sB = mA = mB = 0
for _ in range(N-1):
    A,B = inpl()
    sA += A
    sB += B
    mA = max(A,mA)
    mB = max(B,mB)

if N == 2:
    print(1)
else:
    print(min(sA,sB)+1)