#include <iostream>

using namespace std;

struct Box {
    int Ai;
    int Bi;
};

bool judge(int V, int maxAi, int maxBi, int allAi) {
    if (maxAi > maxBi){
        return false;
    }
    if (allAi > V){
        return false;
    }
    if(maxBi > V){
        return false;
    }
    return true;
}

int main() {
    int T, V, N;
    Box *boxes;
    while (cin >> T) {
        for (int i = 0; i < T; i++) {
            cin >> V >> N;

            int maxAi = 0, maxBi = 0;
            int allAi = 0;
            boxes = new Box[N];
            for (int j = 0; j < N; j++) {
                Box box;
                cin >> box.Ai >> box.Bi;
                if (box.Ai > maxAi) {
                    maxAi = box.Ai;
                }
                if (box.Bi > maxBi) {
                    maxBi = box.Bi;
                }
                allAi += box.Ai;
                boxes[j] = box;
            }
            cout << (judge(V, maxAi, maxBi, allAi) ? "YES" : "NO") << endl;
            free(boxes);
        }
    }
    return 0;
}