#include <bits/stdc++.h>

using namespace std;

#define len(x) int(x.size())
#define all(x) x.begin(), x.end()

typedef long long ll;
/*
ll s(ll x){
    if (x == 0) return 0;
    return (((x + 1ll) * x) / 2);
}

ll n, a, b, c;

ll sum(ll x){
    ll s1 = s(n - x) * a;
    ll s2 = s(x - 1) * b;
    ll res = s1 + s2 + x * c;
    //cout << s1 << ' '<< s2 << ' ' << x * c << endl;
    return res;
}

ll f(ll x){
    vector <ll> t(n + 1);
    for (ll i = 1; i < x; i++){
        t[i] = min(a * i, x * c + (x - i) * b);
    }
    for (ll i = x; i <= n; i++)
        t[i] = min(a * i, x * c + (i - x) * a);
    ll res = 0;
    for (int i = 1; i <= n; i++)
        res = max(res, t[i]);
    return res;
}

int main(){
    #ifdef HOME
    freopen("input.txt", "rt", stdin);
    #endif //HOME
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> a >> b >> c;
    ll l = 0, r = n;
    //cout << sum(3);
    //return 0;
    while(r - l > 1){
        ll len = (r - l + 1) / 3ll;
        ll x1 = l + len;
        ll x2 = r - len;
        ll f1 = f(x1);
        ll f2 = f(x2);
        if (f1 > f2)
            l = x1;
        else
            r = x2;
    }
    ll ans = 1e18;
    ll id;
    for (int i = max(0ll, l - 5); i <= min(n, l + 5ll); i++){
        //cout << i << ' ' << f(i) << endl;
        ll was = ans;
        ans = min(ans, f(i));
        if (was != ans)
            id = i;
    }
    #ifdef HOME
    cout << id << ' ';
    #endif //HOME
    cout << ans;
    return 0;
}*/

map <string, int> cost;

int main(){
    #ifdef HOME
    freopen("input.txt", "rt", stdin);
    #endif //HOME
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    string s;
    cin >> s;
    int n = len(s);
    vector<int> dp(n + 1, 1e9);
    dp[0] = 0;

    cost["I"] = 1;

    cost["IV"] = 4;
    cost["V"] = 5;
    cost["IX"] = 9;

    cost["X"] = 10;
    cost["XL"] = 40;
    cost["L"] = 50;
    cost["XC"] = 90;

    cost["C"] = 100;
    cost["CD"] = 400;
    cost["D"] = 500;
    cost["CM"] = 900;

    cost["M"] = 1000;

    for (int i = 1; i <= n; ++i) {
        for (int j = max(1, i - 4); j <= i; ++j) {
            string p = s.substr(j - 1, i - j + 1);
            if (cost.count(p)) dp[i] = min(dp[i], dp[j - 1] + cost[p]);
        }
    }
    cout << dp[n];
    return 0;
}