#include <stdio.h>
int main(){
    int n,m,p,q;
    scanf("%d%d%d%d",&n,&m,&p,&q);
    
    int one=q*2*m+(12-q)*m,ans=n/one,now=one*ans;
    ans*=12;
    for(int i=1; i<13; ++i){
        if(i>=p&&i<p+q)now+=2*m;
        else now+=m;
        ++ans;
        if(now>=n)break;
    }
    printf("%d\n",ans);
}