class UnionFind:
    def __init__(self, n):
        self.par = [i for i in range(n+1)]
        self.rank = [0] * (n+1)
        self.size = [1 for _ in range(n+1)]
    # 検索
    def find(self, x):
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]
    # 併合
    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if self.rank[x] < self.rank[y]:
            self.par[x] = y
            self.size[y] += self.size[x]
        else:
            self.par[y] = x
            self.size[x] += self.size[y]
        if self.rank[x] == self.rank[y]:
            self.rank[x] += 1
    # 同じ集合に属するか判定
    def same_check(self, x, y):
        return self.find(x) == self.find(y)

n = int(input())
cd = [[int(i) for i in input().split()] for j in range(n)]

c = []
ans = 0

for i in range(n):
    c.append([cd[i][0],n,i])
    if i != 0:
        c.append([cd[i][1],0,i-1])
    ans += cd[i][0]

ki = UnionFind(n+2)
c.sort()
for i in range(2*n-1):
    cost,tmp,v = c[i]
    if tmp == n:
        if not ki.same_check(n,v):
            ki.union(n,v)
            ans += cost
    else:
        if not ki.same_check(v,v+1):
            ki.union(v+1,v)
            ans += cost

print(ans)