#include <bits/stdc++.h>
using namespace std;
#define int long long
// #define endl '\n'
#define ff first
#define ss second
#define pb push_back
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ar array
const int MOD = 1e9 + 7,INF = 1e18, N = 2e5 + 5;
/*
5 2
1 2 2
2 3 2
3 4 2
4 5 2
*/
void solve(){
int s , n;
cin >> s >> n;
vector <int> v(n) , w(n) , k(n);
int sum = 0;
int ans = 0;
for(int i = 0;i < n;i++){
cin >> v[i] >> w[i] >> k[i];
ans = min(s / w[i], k[i]) * v[i];
sum += w[i] * k[i];
}
cout<<ans<<endl;
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int ti = 1;
while (ti--) {
solve();
}
}
