#include "bits/stdc++.h"
#define rep(a,b) for(int a = 0;a < b;a++)
#define REP(i, x, n) for(int i = x; i < n; i++)
#define P(a) cout << a << endl
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
int dx[] = { 1, -1 , 0 , 0 };
int dy[] = { 0,  0,  1, -1 };
ll MOD = 1000000007;

void solve(){
    int a,b,n;
    cin >> a >> b >> n;
    set<int> s;
    rep(i,n){
        int tmp;
        cin >> tmp;
        s.insert(tmp);
    }
    P((a+b)*(n-s.size()));
}

int main() {
    solve();
    return 0;
}