参考程序：

#include<bits/stdc++.h>
using namespace std;
#define ll long long
int n, m;
int cnt[1010];
vector<int> cs[1010];
ll calc(int aim) 
{int cur_cnt = cnt[1];ll res = 0;vector<int> tmp;for (int i = 2; i<=n; i++){int buy = max((int)cs[i].size() - aim + 1, 0);for (int j = 0; j < buy; ++j) {res += (ll)cs[i][j];}cur_cnt += buy;for (int j = buy; j < cs[i].size(); ++j) {tmp.push_back(cs[i][j]);}}sort(tmp.begin(), tmp.end());for (int i = 0; i < aim - cur_cnt; i++) {res += (ll)tmp[i];}return res;
}
int main() 
{cin >> n >> m;for (int i = 1; i <=m; i++) {int p, c;cin >> p >> c;cnt[p]++;cs[p].push_back(c);}for (int i = 1; i <=n; i++) {sort(cs[i].begin(), cs[i].end());}ll ans = 1e18;for (int i = max(cnt[1], 1); i <= m; ++i) {ans = min(ans, calc(i));}cout << ans << "\n";
}