def min_(N, dolls):
    dolls.sort(key=lambda x: (x[1], x[0]))
    inner = [doll[0] for doll in dolls]
    #O(N log N)
    def lis(seq):
        from bisect import bisect_left
        lis = []
        for value in seq:
            pos = bisect_left(lis, value)
            if pos == len(lis):
                lis.append(value)
            else:
                lis[pos] = value
        return len(lis)

    lis_len = lis(inner)
    return N - lis_len
N = int(input())
dolls = []
for _ in range(N):
    r, R = map(int, input().split())
    dolls.append((r, R))

print(min_(N, dolls))