#include <bits/stdc++.h> #define int long long using namespace std; #define rep(i,s,n) for(int i = s;i<n;i++) #define repe(i,s,n) for(int i = s;i<=n;i++) #define rrep(i,s,n) for(int i = (n)-1;i>=(s);i--) #define all(v) (v).begin(),(v).end() #define pb push_back #define fi first #define se second typedef long long ll; typedef pair<int,int>pint; typedef vector<int>vint; typedef vector<pint>vpint; typedef pair<pint,int> P1; typedef pair<int,pint> P2; static const ll maxLL = (ll)1 << 62; const ll MOD=1000000007,INF=1e18; int dy[]={-1,0,1,0}; int dx[]={0,1,0,-1}; int n,m,p,q; signed main(){ cin>>n>>m>>p>>q; int cnt=0; int sum=0; rep(i,1,12+1){ if(p<=i&&i<=p+q-1)sum+=m*2; else sum+=m; } cnt=n/sum; n%=sum; rep(i,1,12+1){ if(p<=i&&i<=p+q-1)n-=m*2; else n-=m; if(n<=0){ cout<<i+cnt*12<<endl; return 0; } } return 0; }