problem

A mysterious $ X $ [cm] plant grows in one place. This plant has the following mysterious properties.

* Say "nobiro" to this plant and it will grow $ A $ [cm].
* Say "tidime" to this plant and it will grow $ B $ [cm].
* If you say "karero" to this plant, it will be $ 0 $ [cm].



However, this plant does not have a negative length. Specifically, when it grows from the state of $ C $ [cm] to $ D $ [cm] $ (C + D \ lt 0) $, it is a plant. Stops growing when it reaches $ 0 $ [cm].

Say one of "nobiro", "tidime", "karero" to this plant only once a day for $ N $ days. Find the length [cm] of the plant after $ N $ days.



output

Print the length of the plant after $ N $ days. Also print a newline at the end.

Example

Input

10 30 10
3
nobiro
nobiro
tidime


Output

80
#include <bits/stdc++.h>
typedef long long ll;
typedef long double ld;
const int INF=1e9,MOD=1e9+7,ohara=1e6+10;
const ll LINF=1e18;
using namespace std;
    
#define rep(i,n) for(int (i)=0;(i)<(int)(n);(i)++)
#define rrep(i,a,b) for(int i=(a);i<(b);i++)
#define rrrep(i,a,b) for(int i=(a);i>=(b);i--)
#define all(v) (v).begin(), (v).end()
#define Size(n) (n).size()
#define Cout(x) cout<<(x)<<endl
#define doublecout(a) cout<<fixed<<setprecision(15)<<a<<endl;
#define Cerr(x) cerr<<(x)<<endl
#define fi first
#define se second
#define P pair<ll,ll> 
#define m_p make_pair
#define V vector<ll> 
#define U_MAP unordered_map<ll,ll>
#define pq priority_queue<ll>
#define rpq priority_queue<ll,vector<ll>,greater<ll>>
#define p_b push_back
    
ll n,cnt,ans,a,b,c,d,tmp,tmpp,m,h,w,x,y,sum,pos,k;
ld doua;
int dy[]={1,0,-1,0};
int dx[]={0,1,0,-1};
//int dy[]={-1,0,1,-1,1,-1,0,1};
//int dx[]={-1,-1,-1,0,0,1,1,1};
string alph("abcdefghijklmnopqrstuvwxyz"),s;
bool fl;
struct edge{int to,cost;};
    
//-------------------------↓↓↓↓↓↓------------------------
    
//------ 自分を天才だと信じる ------
    
int main(void){
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(false);
    
    cin>>x>>a>>b>>n;
    rep(i,n){
        cin>>s;
        if(s[0]=='n')x+=a;
        else if(s[0]=='t')x+=b;
        else x=0;
        x=max(x,0LL);
    }
    Cout(x);
    return 0;
}
