101102c.cpp

/*
 *  101102c.cpp
 *
 *  Oct 24, 2016
 */

#include <iostream>
#include <cstdio>

#include <set>
using namespace std;

typedef pair<int, int> ii;

const int N = int(1e5) + 5;

int a[N], n, q;
set<ii> s;

int main() {
//    freopen("input.inp", "r", stdin);

    int tst; scanf("%d", &tst);
    while (tst--) {
        scanf("%d%d", &n, &q);
        s.clear();
        for (int i = 1; i <= n; i++) {
            a[i] = 0;
            s.insert(make_pair(0, i));
        }

        int res(0), winner(1);
        for (int i = 1; i <= q; i++) {
            int idx, sc; scanf("%d%d", &idx, &sc);

            s.erase(make_pair(a[idx], idx));
            a[idx] -= sc;
            s.insert(make_pair(a[idx], idx));

            __typeof(s.begin()) it = s.begin();
            if (it->second != winner) {
                winner = it->second;
                res = i;
            }
        }

        printf("%d\n", res);
    }
}