// AOJ CGL_3_B Is-Convex
// 2018.5.3 bal4u

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

typedef struct { double x, y; } PP;
typedef struct { PP s, e; } SEG, LINE;

#define INF			1e8
#define EPS			1e-8
#define EQ(a,b)		(fabs((a)-(b))<EPS)
#define PPeQ(a,b)	(EQ(a.x,b.x)&&EQ(a.y,b.y))

int dcmp(double x) { if (fabs(x) < EPS) return 0; return x <= 0 ? -1 : 1; }
PP vset(double x, double y) { PP r; r.x = x, r.y = y; return r; }
PP vadd(PP p1, PP p2) { PP r; r.x = p1.x + p2.x, r.y = p1.y + p2.y; return r; }
PP vsub(PP p1, PP p2) { PP r; r.x = p1.x - p2.x, r.y = p1.y - p2.y; return r; }
PP vsmul(PP p, double k) { PP r; r.x = p.x * k, r.y = p.y * k; return r; }
PP vmul(PP p1, PP p2) { PP r;
	r.x = p1.x * p2.x - p1.y * p2.y, r.y = p1.x * p2.y + p1.y * p2.x; return r; }
double vabs(PP a) { return hypot(a.x, a.y); }
double dist(PP p1, PP p2) {	return hypot(p1.x-p2.x, p1.y-p2.y); };
double cross(PP a, PP b) { return a.x * b.y - a.y * b.x; }
double dot(PP a, PP b) { return a.x * b.x + a.y * b.y; }
double norm(PP a) { return a.x * a.x + a.y * a.y; }

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif
int in()
{
	int n = 0, c = gc();
	if (c == '-') {	c = gc();
		do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
		return -n;
	}
	do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

int ccw(PP p0, PP p1, PP p2)
{
	PP a, b;
	double t;

	a = vsub(p1, p0), b = vsub(p2, p0), t = cross(a, b);
	if (t >  EPS) return 1;	if (t < -EPS) return -1;
	if (dot(a, b) < -EPS) return 2;	if (norm(a) < norm(b)) return -2;
	return 0;
}

int isConvex(int n, PP *p)
{
	int i;

	p[n] = p[0], p[n+1] = p[1];
	for  (i = 0; i < n; i++) {
		if (ccw(p[i], p[i+1], p[i+2]) != 1) return 0;
	}
	return 1;
}

PP p[110];

int main()
{
	int n, i;

	n = in();
	for (i = 0; i < n; i++) p[i].x = in(), p[i].y = in();
	putchar('0'+ isConvex(n, p)), putchar('\n');
	return 0;
}

