from bisect import bisect_left
N = int(input())
LR = [list(map(int,input().split())) for _ in range(N)]
LR.sort(key = lambda x:x[1])
now = 0
ans = N
L = []
for l,r in LR:
    a = bisect_left(L,l + 1)
    if L and a < len(L):
        if L[a] < r:
            L[a] = r
    else:
        L.append(r)
print(N -  len(L))