#include <iostream>

using lint = long long;

void solve() {
    lint n;
    int m;
    std::cin >> n >> m;

    lint px = 0, pt = 0;
    while (m--) {
        lint t, x;
        std::cin >> t >> x;

        lint dx = std::abs(x - px),
             dt = t - pt;
        if (dx > dt) {
            std::cout << "No\n";
            return;
        }

        px = x, pt = t;
    }

    std::cout << "Yes\n";
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}