50分 求助

#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
	long long int n, sum;
	long long int a[2], b[2], c[3];
	cin >> n >> a[0] >> b[0] >> a[1] >> b[1] >> a[2] >> b[2];
	for (int i = 0; i < 3; i++)
	{
		if (n % a[i] == 0)
		{
			sum = n / a[i];
			c[i] = b[i] * sum;
		}
		if (n % a[i] != 0)
		{
			sum = n / a[i] + 1;
			c[i] = b[i] * sum;
		}
	}
	sort(c, c + 3);
	cout << c[0] << endl;
}