#include <cstdio>
#include <algorithm>
using namespace std;
int N, M, X[2][100010];
int greedy(int k, int d) {
int prv = X[k][0], cnt = 1;
for (int i = 1; i < M; i++) {
if (X[k][i] <= prv + d) continue;
prv = X[k][i];
cnt++;
}
return cnt;
}
int main() {
scanf("%d%d", &N, &M);
for (int i = 0; i < M; i++) scanf("%d%d", &X[0][i], &X[1][i]);