#include <stdio.h>
#include <vector>
#include <algorithm>

int main() {
    int n, a, b, c, k;
    std::vector<int> A, B, C, D, E;
    scanf("%d", &n);
    k = n;
    for (int i = 0; i < n; i++) {
        scanf("%d%d", &a, &b);
        A.push_back(a);
        B.push_back(b);
    }
    c = A.size();
    for (int i = 0; i < c; i++) {
        for (int u = 0; u < c; u++) {
            if (B[i] >= A[u] && u != i && A[i] <= B[u]) {
                C.push_back(A[i]);
                C.push_back(A[u]);
                C.push_back(B[i]);
                C.push_back(B[i]);
                std::sort(C.begin(), C.end());
                A[i] = C[1];
                B[i] = C[2];
                k = k - 1;
                C.clear();
                D.push_back(u);
                E.push_back(u);
                c = A.size();
            }
        }
        D.push_back(i);
        E.push_back(i);
        std::sort(D.begin(), D.end());
        std::sort(E.begin(), E.end());
        for (int m = 0; m < D.size(); m++) {
            D[m] = D[m] - m;
            A.erase(D[m] + A.begin());
        }
        for (int l = 0; l < E.size(); l++) {
            E[l] = E[l] - l;
            B.erase(E[l] + B.begin());
        }
        D.clear();
        E.clear();
        c = A.size();
        i = 0;
    }
    printf("%d", k);
    return 0;
}