#include <bits/stdc++.h>
using namespace std;
#include <cstdio>
/** Interface */
inline int readChar();
template <class T = int>
inline T readInt();
template <class T>
inline void writeInt(T x, char end = 0);
inline void writeChar(int x);
inline void writeWord(const char *s);
/** Read */
static const int buf_size = 4096;
inline int getChar() {
static char buf[buf_size];
static int len = 0, pos = 0;
if (pos == len) pos = 0, len = fread(buf, 1, buf_size, stdin);
if (pos == len) return -1;
return buf[pos++];
}
inline int readChar() {
int c = getChar();
while (c <= 32) c = getChar();
return c;
}
template <class T>
inline T readInt() {
int s = 1, c = readChar();
T x = 0;
if (c == '-') s = -1, c = getChar();
while ('0' <= c && c <= '9') x = x * 10 + c - '0', c = getChar();
return s == 1 ? x : -x;
}
/** Write */
static int write_pos = 0;
static char write_buf[buf_size];
inline void writeChar(int x) {
if (write_pos == buf_size)
fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
write_buf[write_pos++] = x;
}
template <class T>
inline void writeInt(T x, char end) {
if (x < 0) writeChar('-'), x = -x;
char s[24];
int n = 0;
while (x || !n) s[n++] = '0' + x % 10, x /= 10;
while (n--) writeChar(s[n]);
if (end) writeChar(end);
}
inline void writeWord(const char *s) {
while (*s) writeChar(*s++);
}
struct Flusher {
~Flusher() {
if (write_pos) fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
}
} flusher;
void flush() {
if (write_pos) {
fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
}
}
const int N = 1e7 + 7;
int n;
int x[N], y[N];
int st[N], top = 0;
bool protect(int i, int j) {
return abs(x[i] - x[j]) <= y[i] - y[j];
}
int main() {
n = readInt();
for (int i = 0; i < n; ++i) {
x[i] = readInt();
y[i] = readInt();
}
for (int i = 0; i < n; ++i) {
while (top > 0 && protect(i, st[top - 1])) {
--top;
}
if (top == 0 || !protect(st[top - 1], i)) {
st[top++] = i;
}
}
writeInt(top, '\n');
return 0;
}
