#include <stdio.h>
#define N 5000
unsigned int X = 12345;
int rand_() {
return (X *= 3) >> 1;
}
int *zz;
void sort(int *ii, int l, int r) {
while (l < r) {
int i = l, j = l, k = r, i_ = ii[l + rand_() % (r - l)], tmp;
while (j < k)
if (zz[ii[j]] == zz[i_])
j++;
else if (zz[ii[j]] < zz[i_]) {
tmp = ii[i], ii[i] = ii[j], ii[j] = tmp;
i++, j++;
} else {
k--;
tmp = ii[j], ii[j] = ii[k], ii[k] = tmp;
}
sort(ii, l, i);
l = k;
}
}
int main() {
static int xx[N], yy[N], yy_[N], ii[N];
static char used[N];
int n, i, i_, j, y, cnt;
scanf("%d", &n);
for (i = 0; i < n; i++)
scanf("%d%d", &xx[i], &yy[i]);
for (i = 0; i < n; i++)
ii[i] = i;
zz = xx, sort(ii, 0, n);
for (i = 0; i < n; i++)
yy_[xx[ii[i]] = i] = yy[ii[i]];
zz = yy, sort(ii, 0, n);
cnt = 0;
for (i = 0; i < n; i++) {
i_ = ii[i];
y = -1;
for (j = xx[i_] - 1; j >= 0; j--)
if (used[j] && y < yy_[j])
y = yy_[j], cnt++;
used[xx[i_]] = 1;
}
printf("%d\n", cnt);
return 0;
}
