#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
#define rep(i, n) REP(i, 0, n)
#define REP(i, s, e) for (ll i = (s); i < (ll)(e); i++)
#define repr(i, n) REPR(i, n, 0)
#define REPR(i, s, e) for (ll i = (ll)(s - 1); i >= (ll)(e); i--)
#define all(r) r.begin(), r.end()
#define rall(r) r.rbegin(), r.rend()

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;

template <typename T, typename U>
T chmax(T& a, const U& b) {
    if (a >= b) return false;
    a = b;
    return true;
}
template <typename T, typename U>
T chmin(T& a, const U& b) {
    if (a <= b) return false;
    a = b;
    return true;
}

void yes_no(bool f, string yes = "Yes", string no = "No") { cout << (f ? yes : no) << "\n"; }

void solve() {
    using D = long double;
    D sx, sy;
    cin >> sx >> sy;
    int n;
    cin >> n;
    using T = tuple<D, D, D>;
    vector<T> ps(n + 1);
    ps[0] = {sx, sy, 0};
    rep(i, n) {
        D x, y, w;
        cin >> x >> y >> w;
        ps[i + 1] = {x, y, w};
    }
    ++n;
    vector<D> ws(1 << n);
    rep(mask, 1 << n) rep(j, n) if (mask & (1 << j)) ws[mask] += get<2>(ps[j]);
    const D inf = 1e18;
    vector d(1 << n, vector<D>(n, inf));
    d[(1 << n) - 1][0] = 0;
    repr(mask, (1 << n)) rep(cur, n) rep(to, n) if (cur != to && (mask & (1 << to))) {
        int nmask = mask - (1 << to);
        auto [a, b, c] = ps[cur];
        auto [x, y, w] = ps[to];
        chmin(d[nmask][to], d[mask][cur] + ((ws[mask] + 100) / 120) * (abs(x - a) + abs(y - b)) + w);
    }
    D ans = d[0][0];
    cout << fixed << setprecision(15);
    cout << ans << "\n";
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int t = 1;
    // multi-testcase
    // cin >> t;
    rep(ti, t) solve();
    return 0;
}