#include <bits/stdc++.h>
using namespace std;

// subtask 3

int main() {
    int T;
    cin >> T;
    int sumN = 0;
    while (T--) {
        int N, M;
        cin >> N >> M;
        vector<int> A(M), B(M);
        for (int i = 0; i < M; i++) {
            cin >> A[i] >> B[i];
            A[i]--;
        }
        sumN += N;
        assert(sumN <= 2'000);
        vector<int> C(M + 1);
        for (int i = 0; i < M; i++) {
            C[i + 1] = C[i] + B[i];
        }
        bool ok = false;
        for (int l = 0; l < N; l++) {
            vector<int> L(M), R(M);
            L[0] = l;
            for (int i = 0; i < M; i++) {
                R[i] = L[i] + B[i] - 1;
                if (i + 1 < M) L[i + 1] = R[i] + 1;
            }
            bool valid = true;
            for (int i = 0; i < M; i++) {
                if (!((L[i] <= A[i] && A[i] <= R[i]) || (L[i] <= A[i] + N && A[i] + N <= R[i]))) {
                    valid = false;
                }
            }
            if (valid) ok = 1;
        }
        if (ok) cout << "Yes" << endl;
        else cout << "No" << endl;
    }
    return 0;
}