PATH TS10 PTNK 2006-2007

#define task "PATH"

#include <iostream>
#include <cstdio>

using namespace std;

using ll = long long;
using ld = long double;

constexpr int N = 1e5 + 5;
int n;
ll s, d;

void Read()
{
    cin >> n >> d;
    for (int i = 1; i <= n; ++i)
    {
        int v;
        char c;
        cin >> c >> v;

        s += v;
    }
}

void Solve()
{
    cout << s * d;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }

    Read();
    Solve();
}