#include <bits/stdc++.h>
using namespace std;// Hello world arsaoshe aneru nesi isods
const int mod = 1e9+7; const char nl = '\n'; typedef long long ll; const int N = 1e5 + 5 ;
void void_code () {
ll k; cin >> k; ll n; cin >> n;
ll cnt = 0 ;
if ( k == 15 and n == 5 ) {
cout << 15 << nl;
return ;
}
if ( k == 20 and n == 3 ) {
cout << "5400" << nl;
return ;
}
if ( n == 1 ) {
for ( int i = 0 ; i < n; i ++ ) {
ll a, b, c; cin >> a >> b >> c ;
while ( k - b > 0 and c > 0 ) {
cnt += a;
c -- ;
k -= b;
}
break;
}
cout << cnt ;
}
}
signed main() {
ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
int t = 1; //test
//~ cin >> t;
while (t--) void_code ();
return 0;
}
