#include #include "unistd.h" using namespace std; #define WA cout<<"char134217728";exit(0) #define RE throw #define TLE sleep(1000) #define FOR(i,a,b) for(int i=(a),i##formax=(b);i=i##formax;i--) #define pb push_back #define mp make_pair #define fi first #define se second #define pcnt __builtin_popcount #define sz(x) (int)(x).size() #define maxs(x,y) x=max(x,y) #define mins(x,y) x=min(x,y) #define show(x) cout<<#x<<" = "<(l,r)(rnd)) #define randDouble(l,r) (uniform_real_distribution(l,r)(rnd)) #define dout(d) printf("%.12f\n",d) typedef long long ll; typedef __int128_t lll; typedef pair pii; typedef pair pll; templateusing V=vector; templateusing VV=V>; templateostream& operator<<(ostream& o,const pair& p){return o<<"("<void Fill(A (&array)[N],const T&v){fill((T*)array,(T*)(array+N),v);} lll gcd(lll a,lll b,lll &x,lll &y){if(!b){x=1;y=0;return a;}lll d=gcd(b,a%b,y,x);y-=a/b*x;return d;} ll gcd(ll a,ll b){lll x=0,y=0;return gcd(a,b,x,y);} ll modInv(ll a,ll m){lll x,y;gcd(a,m,x,y);return (x%m+m)%m;} ll modPow(lll a,lll n,ll m){if(!a)return a;lll p=1;for(;n>0;n>>=1,a=a*a%m)if(n&1)p=p*a%m;return(ll)p;} bool isPrime(ll n){if(n<2||n%2==0)return n==2;lll t=n-1,d=t/(t&-t);for(lll a:{2,325,9375,28178,450775,9780504,1795265022})if(a%n){for(t=d,a=modPow(a,t,n);t!=n-1&&a!=1&&a!=n-1;a=a*a%n,t=t*2%n);if(a!=n-1&&t%2==0)return 0;}return 1;} const int IINF = 1e9+6; const ll LINF = 1e18; const int MOD = 1e9+7; const double PI = acos(-1); const double EPS = 1e-10; static random_device rd; static mt19937 rnd(rd()); const int N = 1e5; int n, m, p, q; main(){ cin.tie(0); ios::sync_with_stdio(false); cin >> n >> m >> p >> q; int c=0; p--; q = p+q-1; while(n){ n -= m; if(p<=c%12 && c%12<=q) n-=m; c++; } cout << c << endl; }