#include<stdio.h>
int main() {
	double a[5000][2];
	int n;
	scanf("%d\n", &n);
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < 2; j++)
			scanf("%d", &a[i][j]);
	}
	int b[2000000];
	for (int i = 0; i < 2000000; i++)
		b[i] = 0;
	for (int i = 0; i < n; i++) {
		int c = (int)(a[i][0] * a[i][1]);
		if (b[c] == 0)
			b[c] = 1;
		else if (b[c] == 1)
			b[c] = 0;
	}
	int d;
	for (int i = 0; i < n; i++) {
		if (b[i] == 1)
			d = i + 1;
	}
	printf("%d", d);
	return 0;
}