1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

ll h, w, n;
ll H, W, ile;
ll d[30];

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> h >> w >> n;
    for (int i = 0; i < n; i++)
        cin >> d[n - 1 - i];

    for (int i = 0; i < n; i++)
    {
        ll ileH = (h / d[i]) * d[i];
        ll ileW = (w / d[i]) * d[i];
        ile += (ileH * ileW - H * W) / (d[i] * d[i]);
        H = ileH;
        W = ileW;

        //cout << H << ' ' << W << ' ' << ile << '\n';
    }

    if (H == h && W == w) cout << ile;
    else cout << -1;

    return 0;
}